Preheat the oven to 350°F (175°C).

In a mixing bowl, combine the pitted cherries, granulated sugar, cornstarch, vanilla extract, and lemon juice. Mix well.

Pour the cherry mixture into a greased baking dish.

In another bowl, mix together the oats, flour, brown sugar, melted butter, and cinnamon until crumbly.

Spread the topping evenly over the cherry filling in the baking dish.

Bake in the preheated oven for 30 minutes, or until the topping is golden brown and the cherries are bubbling.

Remove from the oven and let cool slightly before serving.