Preheat the oven to 425F.

In a large bowl, combine flour, sugar, baking powder, and salt. Cut the butter into ½-inch cubes and add to the mixture. Use a pastry cutter or 2 knives to cut the butter into the flour until it’s crumbly. Pour in 1 ½ cups of the milk and stir. If the dough begins to stick together in a ball, remove it. If not, add more milk, 1 tablespoon at a time, until the dough begins to clump into a ball.

Place the dough on a lightly floured surface. Use your hands to pat the dough into a ¼-inch-thick rectangle, about 12 by 10 inches. Spread a thin layer of jam lengthwise over half the dough and arrange the blueberries in a single layer on top of the jam. Fold the plain dough over the peaches to make a 12 by 5-inch rectangle with jam and blueberries folded inside. Cut the dough into 8 large triangles and sprinkle the top of the scones with the raw sugar.

Bake on an ungreased baking sheet for 10 to 15 minutes, until the scones are a light golden brown. Serve warm or at room temperature.