In a large bowl, combine blueberries, sliced peaches, lemon juice, lemon zest, vanilla extract, granulated sugar and flour. Gently toss until fruit is well coated. Allow the fruit mixture sit while you prepare the crumble topping.
For the crumble topping, take a large bowl and combine the flour, oatmeal, brown sugar, granulated sugar, salt, and cinnamon. Stir together with a whisk. Mix in the butter with your hands until its forms a coarse mixture and there are big crumbles.
Place the fruit mixture in a glass baking dish. Sprinkle the crumble mixture evenly over the fruit. Bake for 40 to 45 minutes, or until the top is browned and crisp and the juices are bubbling. Serve warm with vanilla ice cream.
Crisp can be baked in individual ramekins for 35 to 40 minutes. *The crumble can be prepared ahead of time and stored in the refrigerator for up to two days. Bake when ready!