Ingredients

• 3/4 cup butter, melted and cooled
• 1 cup milk
• 3 eggs
• 1 teaspoon vanilla extract
• 1 1/2 cups granular sucrolose sweetener (such as Splenda®)
• 2 teaspoons baking powder
• 3 cups all-purpose flour
• 1 3/4 cups fresh or frozen blueberries
• 1 1/2 cups malitol brown sugar substitute
• 3/4 cup flour
• 2 teaspoons ground cinnamon
• 1/2 cup butter, softened

Directions
Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9×13 inch baking pan.
In a large bowl, stir together the melted butter, milk, eggs, vanilla and 1 1/2 cups sugar substitute. Combine 3 cups of flour and baking powder; stir into the wet ingredients until just blended. Fold in the blueberries. Spread evenly in the prepared pan.
In a small bowl, stir together the brown sugar substitute, 3/4 cup of flour, and cinnamon. Stir in the softened butter with a fork until the mixture is crumbly. Sprinkle over the top of the cake.
Bake for 35 to 40 minutes in the preheated oven, until a toothpick inserted into the center of the cake comes out clean. This cake is best served warm.

Source >> allrecipes.com