Pre-heat oven to 375°F
Make bottom pastry dough (see below) or use store-bought basic short crust or any crust you prefer. Roll out the bottom dough to fit into the pan and up the sides of the pan.
Bake in the oven for 5-7 minutes or until a very light golden brown. While the crust is cooking cut strawberries in half and add blueberries.
Add 1/2 cup of sugar to berries, juice of 1/2 lemon, and 2 tablespoons of flour, and toss lightly.
Let pastry cool for a minute or two and place the strawberry-blueberry mix into pan just below the edges of the side, drizzle softly melted butter over top of filling.
Roll out top pastry dough (see below) and place on top of filling. If it's fragile place pieces over most of the pie.
If there are no holes (because you are a perfect pastry roller) slice a few into top pastry for pie to breathe while cooking.
Egg wash the pastry by cracking and beating an egg, using a brush to thinly coat the top pastry with wash.
Cook for 30 minutes on the bottom rack and another 15 - 20 minutes on the top, or until golden brown. Let cool for 30 minutes.
Pastry/Pie Crust Preparation:
Bottom pastry: Cut room temperature butter into small cubes, add 1/2 cup of butter and 1 cup of flour and mix gently. Once the dough starts to pull together add 1 cold tablespoon of water, which should make the dough more pliable. If it's still too crumbly you can add a drop more water until it's a bit more sticky but should not be sticking to your hands.
Top pastry: Same method as above except use 1/2 cup of flour and 1/2 cup of icing sugar. This dough will be slightly easier to maneuver.