First things first! Preheat your oven to 400°F (200°C). A hot oven ensures that your puff pastry becomes light and golden.

Next, take your crisp apples. Core and slice them thinly—think golden slices of heaven! If your knife skills are a bit rusty, no worries; just aim for even thickness to ensure they cook evenly. In a medium bowl, toss the apple slices with brown sugar, cinnamon, nutmeg, and lemon zest (if using). Let this mixture sit for around 10 minutes so the flavors can mingle.

Grab your thawed puff pastry sheet. On a lightly floured surface, gently roll it out to a larger size—just enough to fit your tart pan, leaving a little overhang. Don’t press it too hard; you want to keep it airy. Once it’s ready, carefully place it in the tart pan and cut off any excess hanging over the edges.

Now comes the exciting part! Take the apple mixture and layer the slices into the pastry. Arrange them in a circular pattern for a fancy touch, or simply dump them in if you prefer the rustic look—either way, they’ll taste amazing.

Drizzle the gently melted butter over the arranged apples. This step enhances the flavor and ensures the apples roast beautifully.

In a small bowl, mix the egg yolk and milk or cream until combined. Use a pastry brush to apply this luscious mixture to the edges of the pastry. This will give your tart a beautiful golden hue once baked.

Pop your tart into the preheated oven and let it bake for about 25–30 minutes, or until the apples are tender and the pastry is perfectly golden. The kitchen will soon be filled with an aroma that makes it hard to wait.