Rhubarb Custard Pie

This Rhubarb Custard Pie is super easy and is the perfect spring dessert. A par-baked pie crust is filled with chopped rhubarb and then covered with a sour cream custard. This Rhubarb Custard Pie is similar to a Rhubarb Clafoutis or Rhubarb Flan, and is a great make-ahead dessert. It is a great starting point if you are learning how to bake with rhubarb!

Rhubarb Custard Pie

Hi hi! Popping in pretty late in the rhubarb season to bomb you with a whole bunch of rhubarb recipes - I shot these all a few months ago with full intentions of sharing them before now, but we were in the middle of sneakily moving to New Zealand. Turns out an international move during a pandemic takes up a lot of time, so here I am with a bunch of rhubarb recipes late in the season. Sorryyyy.

This Rhubarb Custard pie recipe is a re-make of a rhubarb pie I posted here in 2017 and is a dessert I grew up eating. The original recipe comes from the book 'The Best of Alison Holst' (the one with the red cover, if you know you know), and we knew it as 'rhubarb flan'. Mum and Dad have a rhubarb plant in their garden that grows year round so I used to make this all the time. Rhubarb is such a versatile ingredient and is also delicious paired with strawberries - I use this combination in my strawberry rhubarb pie.

This rhubarb pie is super easy to make. The original used store bought puff pastry but I turned it into a pie recipe with a par baked homemade pie crust, and kept the rest of the recipe the same.

You fill the crust with chopped rhubarb, top it with a sour cream custard, and then bake the whole thing until it's done. It's super easy and just so, so good, and the tart rhubarb flavour really shines through. It's my favourite, and a great, quick way to use up rhubarb.

Custard Pie Filling

This Rhubarb custard pie has a super easy creamy custard pie filling. I make mine with sour cream, and it is poured over the fruit in the pie crust before it goes into the oven.

You may find that you are left with a tiny bit of custard filling left over after filling the pie, depending on how big your rhubarb pieces are, or how big your pie pan is. Try not to over fill the pie too much, however if you are worried about it spilling, place the pie plate onto the sheet pan in the oven before you add the custard.

To remove any bubbles, I like to give the pie a little shake after adding the custard. If there are big bubbles on the surface, you can pop them gently, or quickly blow torch the surface of the custard to remove them.

How to make Rhubarb Custard Pie

There's not too many steps for making this rhubarb custard pie. It is essentially a rhubarb clafoutis, just with a crust. Super easy.

• Make the pie dough - I like to do this ahead of time to give it overnight to chill, and use my homemade pie crust recipe. I also like to make bulk pie dough and keep some in the freezer so that whenever I need it I can just defrost it, so I will often make extra. This recipe makes enough for two single crust pies - just pop the other disc of dough in the freezer for another time.
• Par bake the pie crust - This kick starts the baking of the pastry. This can also be done ahead of time.
• Prepare the rhubarb - The rhubarb gets chopped up and popped into the cooled par-baked pie crust.
• Add the custard and bake - The other component of this rhubarb custard pie is a sour cream custard filling. This is just a whisk together situation - whisk it up and pour over the rhubarb. Then pop the whole thing into the oven and bake until done.
• Chill and serve - This rhubarb custard pie cuts best when it is chilled, so let it cool slightly then throw the whole thing in the fridge to cool down before serving.

Preparing Rhubarb for Baking

If you haven't baked with rhubarb before, this rhubarb custard pie is a great place to start. Preparation wise, you can treat rhubarb a lot like celery. It can be a little stringy, so I like to use my fingernail to just see if I can lift any fibre from the flat part of the rhubarb stalks by starting at the end and seeing if any lifts off. If you can, pull the stringy stuff off and discard, if not then no worries.

The leaves of rhubarb are poisonous so you will often see it sold without them. To prepare the rhubarb just chop it into thin slices. This can be done ahead of time if you like.

To freeze rhubarb just pop it into an airtight bag and freeze. I prefer to freeze it once it is already chopped up.

I haven't tested it myself but this rhubarb custard pie should be fine to make with frozen rhubarb - just defrost before using.

Tips for how to avoid a soggy bottom pie

The par bake on this rhubarb custard pie is essential to avoiding a soggy bottom. It kick starts the baking process of the crust, so it gives it a barrier against the liquid in the filling. It also means that the bottom of the crust has started to bake too. This means you will have a nice flaky pie crust to fill your pie with the wet filling.

If you didn't par-bake your crust you would have to bake the pie at too high of a temperature for the custard in order to bake the crust properly, which would cause all sorts of issues with the custard.

How to line a pie pan with pie dough.

Make sure you start with nice cold pie dough - ideally it will have been chilling for at least two hours or up to overnight.

• Roll out your crust - I like to use a wooden french rolling pin for pie crust but you can use whatever you like! Roll to a circle a little larger than your pie pan. I like to use a 9-inch pie plate.
• Transfer your pie dough to the pan - Flop the dough into the pan and make sure to settle it within the pan so that it doesn't slump.
• Trim if needed - If you have loads of overhang, or your dough isn't a perfect circle, you can trim the edges with some kitchen shears
• Fold and tuck the edges under - Tuck the edges of the crust under themselves to form an edge on your pie dough - this will be what you crimp.
• Chill - At this point, pop your pie dough into the fridge just for a wee bit to allow it to chill down before you crimp.
• Crimp - I like to keep this pretty basic and just do a thumb and fingers crimp, but you can do whatever you like here.
• Chill again - You can freeze your crust here if you want, but I prefer to chill it for about half an hour instead, which I find helps it to keep its shape well in the oven when baking.

How to Par bake a pie crust

The process for par baking a pie crust is pretty simple - it takes a little practice to get the crimp on the crust right, but par baking is a great skill to know how to do!

• Fill with beans or weights - Prick the crust all over, then cover with a crunched up piece of parchment paper. Fill the crust right to the edges with either weights or beans.
• Par-bake - Par bake the pie crust for 15-18 minutes with the weights in, then remove the weights and return the crust to the oven. This second bake is just for a few minutes and will set up the crust that was covered by the paper.

You can par-bake crust ahead of time - just leave it to cool then store lightly wrapped in plastic wrap in an airtight container for up to a day.

Get the full run down in my post: How to blind bake pie crust.

The secret to easy to work with pie dough

I use a little tip that my baking bestie Erin Mcdowell taught me - to laminate my pie dough after making it but before rolling it out for use. What this does it pops a few layers within the pie dough. This makes it homogenous and easy to work with but also still nice and flaky. So you get the best of both worlds - flaky AF pie dough which is super easy to work with. Here's how you do this:

• Make your pie dough - For this recipe I make the dough then form it into a rectangle. Then I wrap tightly in plastic and chill for only an hour. This gives the butter time to chill down enough that it won't melt everywhere when you roll it out.
• Roll out and perform turn 1 - Roll the dough into a large rectangle on a lightly floured surface. Then brush off any excess flour and perform a letter fold - where you fold it like a business letter.
• Perform turns 2 and 3 - Repeat the process again two more times. Your dough should be super homogenous at this point!
• Divide and shape - At this point I split the dough in two and shape each into a disc rather than roll out and laminate each piece individually. Works much better. If you're using it for a lattice top, shape into a rectangle. Starting with the shape you are wanting to achieve makes rolling out much easier!
• Chill again - Either chill your dough for at least 2 hours or overnight, or freeze for another time.

For all my top tips and tricks on how to make the best pie crust, check out my post: How to make homemade pie crust

Butter lumps in your pie crust?

If your butter lumps were too big when you were initially mixing, this rolling out process will be hard. Make sure you incorporate them enough. You want some lumps of butter still in your dough, but not so many that the dough seems lumpy when you roll it out.

Metal vs Ceramic vs Glass pie plates

This is a question that I get often, and I know preference varies from baker to baker. I prefer a metal pie plate. The bottom of the pie gets a good bake, and it is easy to release from the pan. Others prefer ceramic or glass. However, both of those do not conduct heat as well, so things will take a little longer and may bake differently.

There is also the risk of breakage with glass and ceramic. I sometimes pop my crust into the freezer first then into the hot oven. You can't do that with a ceramic or glass pan as you risk the breakage.

Basically, you do you here, but I much prefer a metal pan! I have linked a favourite of mine in the FAQ section.

FAQ for Rhubarb Custard Pie

Can this be made with a store bought pie crust?
Probably, but I haven't tried it (or ever used store bought crust as it wasn't a thing for us growing up!). I assume you would par-bake it first and then proceed with the recipe!

Can this pie be made with other fruit?
You could add some berries along with the rhubarb (which is technically a vegetable) to the pie before adding the custard. Just sub in an equal amount by weight. If you add blueberries you could also rub some lemon zest into the sugar before making the custard.

How to store pie
Store this rhubarb custard pie in an airtight container in the fridge. It will keep for 3 to 4 days.

Can this pie be made in advance?
Yes! It is great to make in advance - it actually needs to be well chilled before cutting to ensure that it cuts cleanly. You can make it a day in advance and store lightly wrapped in the fridge.

How do you tell when a custard pie is done?
The outside edges will be set, and the middle of the pie will be just jiggly.

Help! My pie split!
That's all good - it is totally normal for that to happen as the rhubarb juices react with the custard.

Which pie plate did you use?
I use a vintage aluminium pie plate that I got off of ebay, but this one is a great starter for a pie plate!

What pie weights are best?
I use these ceramic pie weights. I got a couple of sets of them as one isn't enough. However uncooked beans or rice also work great - just set them aside as your baking beans as you can't eat them after they have been baked! My friend Stella also uses sugar!

Why is my pie crust leaking butter?
A little butter leakage is ok but your crust shouldn't be pouring out butter. If it is, you haven't incorporated the butter enough in the initial mixing stage. Then when it hits the oven, it all leaks out.

For more Rhubarb recipes, check out:

Print