1. Prepare the Dough:

1. In a mixing bowl, combine flour and sugar.
2. Cut in the cold butter using a pastry cutter or fork until the mixture resembles coarse crumbs.
3. Add egg yolk and ice water, mixing just until the dough comes together.
4. Shape into a disc, wrap in plastic wrap, and refrigerate for 30 minutes.

2. Prepare the Plum Filling:

1. In a bowl, toss the sliced plums with sugar, brown sugar, cornstarch, cinnamon, lemon juice, and vanilla extract.
2. Let the mixture sit for 10 minutes to allow the flavors to meld.

3. Assemble the Tart:

1. Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
2. Roll out the chilled dough on a floured surface into a 12-inch circle.
3. Transfer to the baking sheet and arrange the plum slices in the center, leaving a 2-inch border.
4. Fold the edges of the dough over the filling, pleating as needed.

4. Bake the Tart:

1. Brush the crust with egg wash and sprinkle with coarse sugar.
2. Bake for 35-40 minutes, or until the crust is golden brown and the plums are bubbling.
3. Let cool for 10 minutes before slicing.

5. Serve & Enjoy:

• Serve warm with vanilla ice cream or a drizzle of honey for extra indulgence!