In a large mixing bowl, combine 2 ½ cups of flour, 2 tablespoons of sugar, and ½ teaspoon of salt. Cut in 1 cup of cold butter until the mixture resembles coarse crumbs. Gradually add 6 to 8 tablespoons of cold water, mixing until a dough forms. Shape it into a disk, wrap in plastic wrap, and chill in the fridge for at least 1 hour.

In a large bowl, toss together about 3 cups of hulled and halved strawberries with 2 ½ cups of chopped rhubarb. Add 1 ¼ cups of sugar, ¼ cup of cornstarch, 1 tablespoon of lemon juice, and 1 teaspoon of vanilla extract. Stir gently until the fruit is well coated and set aside for the flavors to meld.

Roll out half of the pie dough on a lightly floured surface to fit your pie dish. Carefully place the rolled dough into the bottom of the pie dish, letting any excess hang over the edge. Pour the prepared strawberry and rhubarb filling into the crust, spreading it evenly. Dot the filling with 2 tablespoons of butter.

Roll out the second half of the dough for the top crust. Create a solid top with slits for venting or weave strips of dough. Cut a few slits if using a solid crust. Crimp the edges to seal.

Preheat your oven to 400°F (200°C) and place the pie on a baking sheet. Bake for 20 minutes, then reduce the temperature to 350°F (175°C) and bake for an additional 40 to 50 minutes until golden brown.

Remove the pie from the oven and let it cool for 3 to 4 hours on a wire rack.