1-Preheat oven: Preheat oven to 375°F (190°C). Prepare a quarter sheet pan (approximately 9×13 inches).

2-Cut a small X: Cut a small X in the bottom of each peach. Blanch in boiling water for about 45 seconds, then transfer to ice water to cool. Peel skins off.

3-Slice peaches: Slice peaches 1/2 inch thick. Combine slices in a bowl with granulated sugar, ground cinnamon, fresh lemon juice, vanilla extract, cornstarch, nutmeg, and salt. Mix well.

4-Roll out one sheet: Roll out one sheet of puff pastry to fit the bottom and sides of the prepared pan.

5-Use a slotted spoon: Use a slotted spoon to spread the peach mixture over the pastry base, leaving excess juice behind in the bowl.

6-Roll out the second puff pastry sheet: Roll out the second puff pastry sheet. Cut into 10 strips about 1 inch wide.

7-Create a lattice top: Lay half the pastry strips evenly across the pan. Fold back every other strip. Place one strip perpendicular over the unfolded strips. Unfold the folded strips back over the perpendicular strip. Repeat the folding and placing process with the remaining strips to complete the lattice. Trim excess pastry and pinch the edges to seal.

8-Whisk together the egg: Whisk together the egg and 1 tablespoon water to make an egg wash. Brush this wash over the pastry lattice. Sprinkle generously with coarse sugar.

9-Bake: Bake for 30-40 minutes, or until the pastry is deep golden brown and the filling is bubbly. If the crust browns too quickly, cover loosely with aluminum foil.

10-Cool in the pan: Cool in the pan on a wire rack for 15-20 minutes before slicing into bars. Serve warm with vanilla ice cream.