"This is a very easy and tasty coffee cake that kids can help mix. It's great reheated and it's comforting on cold winter mornings. This recipe can be modified hundreds of ways so be creative and make it yours. Enjoy with ice cream, whipped cream, or both!"
Preheat oven to 400 degrees F (200 degrees C). Grease a 9x11-inch baking pan.
Mix 2 cups baking mix, boysenberries, milk, egg, 2 tablespoons brown sugar, and vanilla extract in a bowl until batter is moist, about 30 seconds. Pour batter into baking pan.
Combine 1/3 cup baking mix, 1/3 cup brown sugar, and ground cinnamon in a bowl; cut in 2 tablespoons butter with a fork, until mixture resembles coarse crumbles. Sprinkle crumbles over the batter until covered.
Bake in the preheated oven until a toothpick comes out clean, 20 to 25 minutes.