The Best Tiny Berry Crostata!

Name: Summer Berry Crostata
Ingredients: 1/2-inch disc of pie dough; 1 blackberry, sliced; 1 strawberry, sliced; 1 cherry, sliced; 1/2 teaspoon cornstarch; 1/2 teaspoon sugar; 1/4 teaspoon lemon juice; Egg wash; Raw sugar; Whipped cream