Make the dough: In a bowl, whisk flour, 2 tablespoons sugar, and salt. Cut in the butter until the mixture looks like cornmeal with a few pea-sized chunks. You want some texture, not a smooth paste.
Add water slowly: Drizzle in ice water a tablespoon at a time until the dough holds together. Don’t overwork—we’re going for flaky, not rubbery.
Chill: Shape into a disk, wrap, and refrigerate at least 30 minutes. If you’re rushed, you can toss it in the freezer for 15 minutes, but not longer or you’ll be chiseling a hard lump.
Prepare the filling: In a bowl, toss apples with 1 tablespoon sugar, lemon juice, cornstarch, and vanilla. Let them mingle as you crush your raspberries gently—no need to turn them into sauce, we want some berry bite.
Roll out the dough: On a floured surface, roll into a rough circle about 12 inches across. Don’t stress about perfect edges—this is rustic charm at work.
Assemble: Pile the apples in the center, layering with raspberries. Drizzle any juice from the bowl over the fruit. Fold the edge of the dough over the fruit, pleating as needed to create a border.
Bake: Place on a parchment-lined baking sheet. Brush the crust with milk or an egg wash and sprinkle with a touch more sugar if you like extra sparkle.
Cook until golden and bubbly: About 40–45 minutes at 375°F (190°C). If the edges brown too quickly, cover them with foil for the last 10 minutes.
Cool briefly: Let the galette rest 15 minutes before slicing to keep juices from running everywhere. Then cut and serve with a grin.