PIE DOUGH

1. Place flour, sugar and salt into a large bowl. Cut butter into chunks, and add to the flour. Toss lightly to coat.
2. Working quickly, using a pastry blender or  your fingers,  cut the butter into the flour mixture until there are only large pea-sized chunks left. You want a few lumps of butter remaining to keep the pastry nice and tender.
3. Combine ice, water and cider vinegar in a bowl. Sprinkle a few tablespoons of the ice water into the flour and butter mixture, and using a stiff spatula or your hands, mix in well. Continue adding water a tablespoon at a time ( I usually start with about 120g liquid, mix that in, then go from there and add additional liquid as needed) until you have a dough that holds together well, but is not too wet.
4. Squeeze together with your fingertips to make a homogenous dough. Shape into a rectangle, Rest in the fridge for one hour.
5. Roll out the dough on a floured surface into a rectangle, fold it in thirds like a letter, then roll again and repeat the folding. Repeat this process one more time. Divide the dough into two pieces, and shape each into a disc by folding the edges under. Rewrap tightly in plastic, and rest for at least two hours, or preferably overnight, before using.
6. Once the dough has rested, unwrap one disc and place on a lightly floured surface. Roll out to 1/4” (6mm) in thickness, turning the dough 45˚ often as you are rolling to keep it even. You want the circle to be slightly larger than your pie tin. Transfer to a 9” pie tin, and arrange to ensure that the dough is well settled.
7. Trim the dough using scissors or a sharp knife, leaving about one inch excess around the edges. Gently tuck the dough under and onto itself, to give you a neat folded edge. Chill in the fridge for 15-20 minutes, then remove from the fridge and crimp as desired. Dock all over with the tines of a fork, then chill for a further 30 minutes, or freeze for 20 minutes or until solid.
8. While the crust is in the fridge, preheat the oven to 425˚f / 220˚c. Cut a piece of parchment slightly larger than the pie dish. Line with the parchment paper and fill with pie weights or dried beans, filling right to the bottom of the crimps.
9. Place the pie tin on a baking sheet, and place in the oven. Bake for 18-20 minutes, or until the edges are slightly golden brown. Remove from the oven, remove the parchment paper and beans. Return to the oven and bake for a further 2-3 minutes, until the inside of the crust is set and barely golden.
10. Remove from the oven and allow to cool completely. 

STRAWBERRY RHUBARB PIE FILLING

1. Combine the strawberries, rhubarb, vanilla, salt, and 100g of the sugar in a medium saucepan. Cook over medium heat, stirring occasionally, until the mixture comes to a boil.
2. Continue to cook for a further 5 minutes. Combine the remaining 150g sugar and corn starch in a small bowl. Turn the heat to low and add the sugar mixture to the saucepan. Stir well until thickened. Remove from the heat and transfer to an airtight container or sheet pan.
3. Press a piece of plastic wrap directly against the surface of the filling. Allow to cool completely, or store in the fridge until ready to use.

CRUMBLE PIE TOPPING

1. Place the butter in a medium saucepan. Cook until the butter has melted, and then continue to cook, swirling the pan often, until the butter foams and turns golden brown and nutty - this should take 3-4 minutes.
2. Weigh out 150g (see Notes section below) of the brown butter and set aside. In a separate medium bowl, whisk together all the other ingredients. Add the brown butter and mix with a spatula until the mixture forms lumps. Store in an airtight container in the fridge until ready to use. 

ASSEMBLY

1. Preheat the oven to 400°f / 205°c. Place the cooled par-baked pie crust in the pan on a baking sheet. Transfer the cooled strawberry rhubarb filling to the pie crust and smooth down with a spatula, ensuring that there are no large air bubbles.
2. Top the pie with the streusel - there will be quite a lot of it. Spread it so it is evenly spread over the surface of the pie.
3. Cover the pie with foil and place in the oven. Bake for 40 minutes with the foil on, then remove the foil and bake for a further 20 minutes until the streusel is golden brown and the filling is bubbling.
4. Remove from the oven and leave to cool completely before slicing and serving.
5. Store leftovers in an airtight container either at room temperature or in the refrigerator.