Adapted from Food52
Take your dough out of the fridge 20 minutes before rolling it out (or 1 hour before if it's in the freezer).
Preheat your oven to 450° F. Fully cover a sheet pan (measuring at least 12 1/2-inches in width) with foil and place the pan in the oven to heat up.
Cut a piece of parchment paper that's about a 12-inch square. Roll out your dough into about a 12-inch round. It doesn't need to be perfect -- you're going to fold over the edges. Roll dough onto your rolling pin. Unroll dough onto the piece of parchment.
Using a very sharp knife or a mandoline, with the apple stem facing north, very thinly slice about 5 circles off of two opposing sides of the apple. Stop once you hit the core. Repeat with the remaining apples. Save remaining apple and the outermost discs with lots of skin for applesauce or some other use.
Starting about 2 inches in from the border of the rolled out dough, make a circle with the apple discs, having them overlap considerably. Continue with a second layer that overlaps the larger circle. Do a third and smaller circle. And a fourth. Finish it off with a few discs in the middle creating a flower pattern. Paint all exposed apple surface with the brown butter vanilla rosemary mixture. Fold the outer border of the dough in to enclose about half of the exterior edge of the outermost apple discs. It can be creased and uneven to give it a rustic appearance.
Whisk together egg and heavy cream. Paint exposed border of dough with a thin layer of egg wash. Refrigerate any leftover egg wash and save for your next tart or pie (it will last a few days). Generously sprinkle the turbinado sugar all over the apples and the egg-washed dough.
Warm up the apricot jam. Using a pastry brush, paint surface of the cooked apples with the warm jam. Serve immediately.