A classic double-crust apple cobbler loaded with cinnamon-spiced Granny Smith apples baked low and slow until the filling is jammy and the crust is deeply golden. Inspired by Michelle Obama's recipe.
Combine the sliced apples, brown sugar, cinnamon, nutmeg, salt, and flour in a large bowl. Toss well so every slice is coated. Cover and refrigerate overnight to let the spices fully penetrate the apples.
Preheat the oven to 325 °F (165 °C). Grease a large baking dish with butter and dust it lightly with flour.
Roll the pie crusts out thin. Line the bottom and sides of the dish with 1 1/2 crusts, then prick the dough all over with a fork.
Pour the apple filling into the crust along with any accumulated juices. Cut about 3/4 of the butter stick into small pieces and dot them evenly across the top of the apples.
Lay the remaining 1 1/2 crusts over the filling. Press and pinch the edges together to seal.
Melt the remaining butter and brush it generously over the top crust.
Lower the oven temperature to 300 °F (150 °C). Bake for up to 3 hours, checking at the 2 1/2-hour mark to make sure the crust isn't browning too quickly. The cobbler is done when the top is deep golden and the filling bubbles through any cracks.