Mix 3 tablespoons melted butter, brown sugar, granulated sugar, vanilla extract, lemon zest and lemon juice together in a medium mixing bowl. Add peaches and blueberries. Mix to combine. Pour into a baking dish.
Top with granola cereal and the remaining melted butter. Bake for 25 to 30 minutes. Allow to cool for about 5 minutes. Serve warm topped with vanilla ice cream.
Crumble can be stored in the refrigerator for 1 to 2 days, reheat so it's warm before serving.