PREHEAT oven to 425 degrees F.
MAKE SAUCE: In a food processor puree 5 cups strawberries with sugar and force through a fine sieve into a bowl. Slice remaining strawberries and stir into sauce with raspberries, blueberries, and blackberries.
MAKE SHORTCAKES: In a large bowl sift together flour, baking powder, sugar, and salt and with a pastry blender or your fingertips blend in butter until mixture resembles coarse meal. In a bowl whisk together cream, egg, and vanilla and with a fork stir into flour mixture, stirring until mixture just forms soft dough.
ON a lightly floured surface with floured hands pat dough out into a circle about 1/2 inch thick and with a 3-inch round cutter cut out 6 rounds. Place rounds on a large baking sheet. Brush tops with milk and sprinkle with sugar and almonds. Bake in middle of oven until golden, about 15 minutes. Cool shortcakes on a rack.
SPLIT shortcakes horizontally and arrange bottom halves on plates. Spoon sauce over bottom halves and top with whipped cream. Arrange shortcake tops on whipped cream and garnish with mint sprigs. Serves 6.