In a large mixing bowl, combine the all-purpose flour, salt, and sugar. Using a pastry cutter or your fingers, cut in cold butter until the mixture resembles coarse crumbs. Gradually add ice water, stirring until the dough comes together. Wrap the dough in plastic wrap and chill in the refrigerator for at least 30 minutes.

While the dough chills, prepare the delicious filling. In a separate bowl, toss together the fresh strawberries, rhubarb, sugar, cornstarch, vanilla extract, lemon juice, and a pinch of salt. Allow the mixture to sit for 10-15 minutes.

Once your pie crust has chilled, lightly flour your work surface and roll the dough into a 12-inch circle, keeping it about 1/8 inch thick. Carefully transfer the rolled dough into a 9-inch pie dish, gently pressing it into place.

Pour the strawberry-rhubarb filling into the prepared crust, spreading it evenly. Dot the filling with small pieces of cold butter. Optionally, create a lattice design with remaining dough or cover with a full crust with slits for steam.

Preheat your oven to 425°F (220°C). Bake for 15 minutes until the crust edges begin to brown, then reduce temperature to 350°F (175°C) and continue baking for an additional 45-50 minutes.

Let the pie cool on a wire rack for at least 2 hours to allow the filling to thicken.