These Mud Pie Bars are the perfect chocolate dessert for any chocolate lover. They have a layer of chocolate crumbs, followed by a layer of chocolate cake, then a layer of chocolate mousse. These chocolate mousse bars are then finished off with a layer of whipped cream and chocolate curls.
Table of contents
Mud Pie Bars from Sarah Kieffer's Book, 100 Cookies
Sarah's first book, 'The Vanilla Bean Baking Book', is probably one of the most used in my collection. Her recipes are amazing, work every time, and are so well written, so I will often turn to it for reference. It is so amazing that I just knew this new book would be incredible. And turns out, it's even more incredible than I could have even imagined.
The book is called '100 cookies' and is just that - 100 cookie recipes. There's her famous pan banging cookies, a section for brownies and blondies (my go-to brownie is her recipe!), then little treaty things, and a whole lot of bars and sandwich cookies. You're going to need to pick yourself up a copy ASAP.
The ultimate chocolate lover's dessert.
I had a really hard time deciding what to make from Sarah's book to share here, until I flipped to these mud pie bars. They are made up of four layers, so are a little more labour intensive than your standard bar. However, every second of work is 100% worth it, as the final outcome is rich and chocolatey - to me, this is the perfect chocolate dessert.
Four layers of Mud Pie Bars
Part of what makes these so, so impressive are the four layers, which are:
- Chocolate Crumbs: The first layer is a thin layer of chocolate crumbs. Sarah calls for chocolate wafer cookies. However I didn't have any, so I gutted some oreos and crushed those up instead, and they worked great.
- Chocolate Cake: The next layer is a chocolate cake layer poured over the chocolate crumbs. This cake is rich and dense, and provides the perfect base for what is coming next.
- Chocolate Mousse: A rich, silky, chocolate mousse is made and allowed to set, and then spread over the base and left to chill for a wee bit to firm up.
- Whipped Cream: Finally, the whole thing is finished off with a thin layer of whipped cream and a coating of chocolate curls. The cream cuts perfectly through the rich chocolate.
How to break up the work load of a complex baking project
These Mud Pie Bars have a few elements, so you can easily break up the work! Here's how I did it:
- Day one:
- Make the chocolate crumb layer and leave to cool.
- Bake the chocolate cake layer and leave to cool (it needs four hours in the fridge at least).
- Make the chocolate mousse and leave to set overnight.
- Day two:
- Add the chocolate mousse layer to the bars and leave to chill
- Add the whipped cream layer and serve!
FAQ for Mud Pie Bars
If you don't have chocolate wafers, Oreos work perfectly. I removed all the filling then ground up the cookies.
If you would like to make these gluten free it would be very easy, as the cake has very little flour in it. Just swap the all-purpose flour for a 1:1 gluten free swap, and use a gluten free oreo in the base.
These keep great in the fridge! Sarah said they are best after two days, but we had some on day five and they were still great. If you are worried you can leave off the whipped cream topping on half and add fresh cream at a later date.
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Made this recipe and love it?
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A note on salt and oven temperature
It is important to note the type of salt that is called for in a recipe. I use Diamond Crystal salt throughout my recipes - if you use a different sort of kosher salt or regular table salt you will need to adjust accordingly as some salt is 'saltier' than others. Morton's salt is twice as salty, so you will need half the quantity. Same goes for a regular table salt. I am working to get gram measurements throughout my recipes for salt but still getting there.
All oven temperatures are conventional unless otherwise stated. If you are baking on fan / convection, you will need to adjust the temperature. An oven thermometer is a great investment to ensure that your oven is the correct temperature.
Using the double / triple function in the recipe card
You will notice that there is a '1X' '2X' '3X' button in my recipe card. This can be used for doubling or tripling a recipe. However, please note that this only doubles the ingredient quantities in the ingredients list and NOT in the method. If there are quantities or pan sizes in the method of the recipe (for example weigh out 150g brown butter), you will need to scale this number manually. It will also not change the baking time in the recipe so you will need to adjust this yourself too. It is always a good idea to read through a recipe fully before doubling it just to check this. If you would like to scale this recipe or convert for another pan size, use my calculator!
Tools and equipment
For a list of my go-to tools and equipment, I have a post you can refer to here.
Why is this recipe in grams?
I post my recipes in grams as it is the most accurate way to bake. Cups are not only inaccurate but they vary in volume worldwide. There is no way for me to provide one cup measure that works for everyone. However, posting in weight fixes this issue. If you would like the recipe in cups you are welcome to convert it yourself via google, but please do not ask me to do it for you as I am not comfortable providing a recipe using a method that I have not tested. Baking with a scale is easy, accurate, and also makes cleanup super simple. Here is the scale that I use if you would like a recommendation! Here's to accurate baking!Print
These Mud Pie Bars are the perfect dessert for any chocolate lover. They have a layer of chocolate crumbs, followed by a layer of chocolate cake, then a layer of chocolate mousse. They are then finished off with a layer of whipped cream and chocolate curls.
- 200g chocolate wafer cookies or oreos with the filling taken out
- 70g unsalted butter, melted and cooled
- 225g semisweet or bittersweet chocolate
- 170g unsalted butter
- 2 Tbsp Dutch process cocoa powder
- 250g granulated sugar
- 5 large eggs, at room temperature
- 1 tsp vanilla extract
- ¼ tsp salt
- 36g all-purpose flour
- 600g heavy cream
- 5 large egg yolks, at room temperature
- 50g granulated sugar
- ¼ tsp salt
- 1 tsp vanilla extract or paste
- 225g semisweet or bittersweet chocolate, finely chopped
- 360g heavy cream
- 2 Tbsp granulated sugar
- 1 tsp vanilla bean paste or extract
- pinch of salt
- Adjust an oven rack to the middle of the oven. Preheat the oven to 350°f / 180°c.
- Grease a 9" x 13" (23 x 33cm) pan and line it with a parchment sling.
- Place cookies in the bowl of a food processor and process until broken down into fine crumbs. Move the crumbs to a medium bowl, and pour the melted butter over the top. Use a spatula to stir together until combined.
- Press the mixture onto the bottom of the prepared pan and bake for 10 minutes. Remove the pan from the oven and let cool.
- Keep the oven temperature at 350°f / 180°c.
- In a small saucepan, melt the chocolate and butter together over low heat, stirring frequently, until smooth. Remove from the heat and stir in the cocoa powder.
- In a large bowl, whisk together the sugar, eggs, vanilla, and salt until smooth. Add the flour and mix again until combined. Add the warm chocolate and whisk into the batter until combined. Let the mixture sit for 15 minutes.
- Pour the cake batter over the cooled, baked crust and use an offset spatula to smooth the top.
- Bake the cake until the edges are set and the center jiggles slightly, 15 to 18 minutes. Remove from the oven and let cool completely on a wire rack. Cover the pan with plastic wrap and refrigerate for 4 hours, or overnight.
- Heat 240g of the heavy cream in a small, heavy saucepan until hot.
- In a medium saucepan off the heat, whisk the egg yolks. Whisking constantly, slowly add the sugar to the egg yolks, then the salt, and then slowly pour in the warmed heavy cream. Cook over medium heat, stirring constantly, until the mixture registers 160°f / 70°c. Pour the mixture through a fine-mesh sieve into a large bowl and stir in the vanilla.
- In a small saucepan over low heat, melt the chocolate, stirring frequently until smooth. Whisk the chocolate into the custard until smooth, then let cool.
- In the bowl of a stand mixer fitted with the whisk attachment (or just using a mixing bowl and whisk), beat the remaining 360g heavy cream until stiff peaks form. Whisk one-third of the whipped cream into the chocolate custard to lighten it, then gently fold in the remaining whipped cream.
- Transfer the mousse to a large bowl and cover the bowl with plastic wrap. Refrigerate for 4 hours, or overnight.
- Ten minutes before whipping the cream, place the bowl and whisk from a stand mixer (or a hand whisk) in the freezer and let chill. In the chilled bowl, whisk together the heavy cream, sugar, vanilla, and salt for 30 to 45 seconds. Increase the speed to medium and beat for 30 to 45 seconds. Increase the speed to high and beat until the cream is smooth, thick, and nearly doubled in volume, 30 to 60 seconds. The whipped cream can be made 2 hours ahead and stored in the fridge.
- Transfer the chilled chocolate mousse onto the top of the baked, cooled cake. Use an offset spatula to even the top. return the bars to the fridge and let chill for 1 hour.
- When ready to serve, cover the bars with the whipped cream. Coat the top with grated chocolate, if desired. Use the parchment sling to remove the cake from the pan, and cut into slices. Bars can be stored in the fridge in an airtight container for up to 5 days.
Reprinted with permission from '100 Cookies' by Sarah Kieffer. Sarah uses table salt in her recipes which is 'saltier' than kosher. If you are using Kosher salt, increase your quantities.
Keywords: sarah kieffer, 100 cookies, mud pie, mud pie bars, chocolate