1. Make the Pie Dough

- In a food processor, combine flour, sugar, and salt; pulse to mix.

- Add cold butter cubes and pulse until the butter forms pea-sized pieces.  

- Slowly drizzle in the ice water while pulsing, just until the dough comes together when pinched.

- Turn the dough onto a floured surface; gently knead 2–3 times.

- Shape into a disc, wrap, and chill for at least 2 hours (or overnight).

2. Prepare the Apple Filling

- Preheat oven to 400°F (200°C).

- Line a rimmed baking sheet with parchment.

- Peel and slice apples into thin ⅛-inch slices.

- Toss apples with lemon juice, sugar, and cinnamon.

3. Assemble the Galette

- Roll chilled dough into a 12-inch circle on a floured surface.

- Transfer to the lined baking sheet.

- Pile the apple filling in the center, leaving a 3-inch border.

- Drizzle melted butter over the apples.

- Fold the edges up and over the fruit, pleating as you go.

- Brush crust with egg wash and sprinkle with sanding sugar (optional).

4. Bake & Serve

- Bake for 45 minutes, until the crust is golden brown and the apples are tender.

- Let cool slightly before slicing.

- Serve warm — delicious with vanilla ice cream or whipped cream.