Step 1

Make the crust. Combine the flour, salt and butter in a large bowl. Gently cut the butter into the flour using 2 sharp knives in a crisscross motion until the butter is about the size of small peas. (The lighter the hand, the flakier the crust.) Slowly drizzle in 1/2 cup ice water and fold into the mixture with a fork until the dough comes together-you want to work the dough as little as possible. Add more water, 1 tablespoon at a time, if the dough is too dry. Turn the dough out onto a floured surface and divide into 2 balls. Form each into a disk, wrap in plastic and refrigerate at least 30 minutes. Meanwhile, trim the rhubarb and cut into 1/2-inch pieces. Hull the strawberries and slice. Combine the rhubarb, strawberries, granulated sugar, flour, cinnamon, salt, vanilla and lemon juice in a large bowl; toss.

Step 2

Prepare the bottom crust. Preheat the oven to 425 degrees F. Roll out 1 disk of dough on a floured surface into a 12-inch round. Roll the dough onto the rolling pin, then carefully unroll it over a 9-inch pie plate. Gently press the dough into the plate with your fingers. Add the strawberry-rhubarb filling. Do not trim the overhanging dough.

Step 3

Make the lattice. Roll out the remaining disk of dough into a 12-inch round. With an old-fashioned crimper, sharp knife or pizza cutter, cut into 1-inch-wide strips. Lay about half of the strips on the pie in one direction, about 1/2 inch apart. Fold back every other strip halfway. Lay a strip perpendicular to the first ones. Unfold the strips back over the new strip, then fold alternate strips back halfway. Add another perpendicular strip; unfold the strips back over it. Repeat to form a lattice. Pinch the overhanging top and bottom crusts together, trimming as needed, then fold the dough under itself and crimp with your fingers.

Step 4

Bake the pie. Using your fingers, pat the lattice top with milk and sprinkle with coarse sugar. Put the pie on a baking sheet and place in the preheated oven. Bake 20 minutes, then reduce the oven temperature to 375 degrees F and bake until the crust is golden brown and the filling is bubbling, 50 more minutes. Let cool completely before slicing.