Preheat oven to 350˚F (180˚C) and grease a 9 1/2-inch (24 centimeter) round tart pan with removable base with butter.
On a lightly floured surface, roll the larger disc of dough into a round sheet wide enough to cover the bottom and sides of the pan, about 1/3 inch (8 millimeters) thick.
Gently transfer to the prepared pan, using your fingers to press the crust completely against the bottom and sides, making sure there are no air bubbles or gaps. If the dough tears, gently press back together or use any excess pieces of dough from the edges to patch.
Prick across the bottom of the dough a few times with a fork.
Cover evenly with the jam.
On a lightly floured surface, roll the second piece of dough into round sheet about 1/4 inch (6 millimeters) thick.
Cut into 3/4 inch (2 centimeter) wide strips. Place the strips over the filling diagonally in one direction about 1 inch (2.5 centimeters) apart. Repeat in the opposite direction diagonally to make a lattice pattern. Neatly press the strips along the edges to seal the dough and cut away any excess.
Place the pan on a rimmed baking sheet and transfer to the preheated oven.
Bake until the crust is golden brown around the edges and the jam is thick and bubbly, 30-40 minutes.
Allow to cool to room temperature in the pan before removing, slicing, and serving.
If desired, dust the top of the crostata with powdered sugar.