Ingredients

• 1 , 15.25 ounce
• 3 ounces white cake mix extender , See Cook's Note
• 2.25 cups water , divided
• 4 eggs whites
• 0.33 cups vegetable oil
• 1 cup white sugar
• 2 tablespoons cornstarch
• 1.5 cups fresh blueberries
• 1 teaspoon fresh lemon juice

Instructions

1. 1 Preheat the oven to 350 degrees F (175 degrees C). Grease and lightly flour a 9x13-inch baking pan.
2. 2 Beat cake mix, cake mix extender, 1 ¼ cups water, egg whites, and oil together in a large bowl with an electric mixer on low speed until moistened. Pour batter into the prepared pan.
3. 3 Bake in the preheated oven until a toothpick inserted into center comes out clean, 32 to 36 minutes. Cool cake on a wire rack, at least 25 minutes.
4. 4 Meanwhile, combine sugar and cornstarch in a small saucepan; stir in remaining 1 cup water. Bring to a boil over medium heat, stirring constantly. Add blueberries and lemon juice; cook and stir until blueberries burst and sauce turns a deep purple color, about 10 minutes. Mash any berries that did not burst. Cool.
5. 5 Poke holes into cake, about every inch, using the handle of a wooden spoon; slowly pour blueberry sauce over top. Chill in the refrigerator before slicing.

Nutrition per serving