Preheat the oven to 375°F. Gently wash & dry the blackberries with a clean cloth or paper towel.

Add the berries to a bowl along with the white sugar, cornstarch and lemon juice. Gently stir/toss the blackberry ingredients together and set the bowl to the side.

In a separate bowl or food processor add the crisp topping ingredients: oats, flour, brown sugar, cinnamon, salt and cold butter. Crumble the ingredients together using one of these methods: with clean hands, with a pastry cutter, or pulsing for several seconds in a food processor; until a crumble mixture starts to form.

Transfer the blackberries into a small-medium size baking dish. I am using a 9.5 x 6.5 x 2 in / 1.5 qt dish. Evenly add the oat crisp topping on top of the blackberries. Bake for 30-35 minutes or until the topping is golden brown. Some of the blackberries may start to bubble around the sides of the baking dish as it bakes.

Remove crisp from the oven and let it cool for 5 minutes. Enjoy warm by itself or with a big scoop of vanilla ice cream!