In a large bowl, whisk together flour, salt, and sugar.

Add the cold cubed butter. Use a pastry cutter or your fingertips to work the butter into the flour until the mixture resembles coarse crumbs with pea-sized pieces of butter remaining.

Sprinkle ice water over the mix, a tablespoon at a time, tossing with a fork until dough just comes together.

Divide into two disks, wrap in plastic, and chill for at least 30 minutes (or up to 2 days).

Method A — Stovetop compote (quick): In a small saucepan over medium heat, combine peaches, blueberries, sugar, honey, lemon juice, lemon zest, cinnamon, and a pinch of salt. Cook for about 6–8 minutes until the fruit begins to release juices and soften.

Stir in the cornstarch slurry and cook for 1–2 more minutes until thickened.

Method B — Roasted fruit (deeper flavor): Preheat oven to 400°F (200°C). Toss peaches and blueberries with other filling ingredients on a sheet pan and roast for 12–18 minutes.

Preheat oven to 375°F (190°C) and line a baking tray with parchment.

Roll one dough disk on a lightly floured surface to about 1/8-inch thickness. Use a round cutter to stamp out circles.

Place a tablespoon of filling in the center of each circle and fold over to seal.

Cut small slits on top for steam vents, brush with egg wash, and sprinkle with coarse sugar if desired.

Bake for 18–22 minutes or until golden brown.

Let cool for 5 minutes on the tray before transferring to a rack.