Preheat oven to 400° and lightly spray a 3 quart baking dish with non stick spray.
For The Crisp Topping
In a medium bowl, whisk flour, brown sugar and oats together.
Cut 1 cup of butter into small pieces and add to flour mixture (save the other ¼ cup to add on top of cherries).
Using two forks or a pastry cutter, cut butter into flour mixture until crumbly. Set aside.
For The Cherry Filling
Add rinsed cherries to a large bowl and pour lemon juice over cherries. Stir.
In a small bowl, whisk sugar, cinnamon, nutmeg, salt and corn starch together then sprinkle over cherries. Stir to make sure cherries are coated. After sitting about 5 minutes, stir again and give it a quick stir right before pouring into prepared baking dish.
Pour cherry mixture into prepared baking dish and slice remaining butter and randomly place on top of cherries.
Spread flour mixture over cherries and place in the oven and bake for 50-55 minutes or until topping is golden brown and cherry filling is hot and bubbly.
Carefully remove from oven and let sit 15 minutes before serving. Serve warm with a scoop of vanilla ice cream or whipped cream.