Step 1

Preheat oven to 350° F. Spray or grease a 6-inch cast iron skillet and set aside.

Step 2

Heat a small saucepan over medium-high heat. Add blackberries, sugar and lemon juice and stir to combine. Bring to a boil, reduce heat to medium, add cornstarch and simmer until blackberries just start to breakdown, about 3-4 minutes.

Step 3

Transfer blackberries to prepared skillet and set aside while you prepare the crumble topping.

Step 4

In a small bowl, combine flour, oats, sugar, salt, cinnamon, oil and lemon juice. Mix together with a fork until all ingredients are moistened and small clumps start to form. Pour crumble toping over blackberries and spread out into an even layer, leaving some edges exposed.

Step 5

Bake crumble for 20-25 minutes until crust is a light golden brown. Allow to cool for 5 minutes and top with a scoop of vanilla ice cream or Greek yogurt if desired. Enjoy!