In bowl mix together your cake mix, 1 egg and 1 stick butter.
Spray a 9x13" baking pan with non stick cooking spray and spread mixture over bottom, set aside.
In another bowl beat your cream cheese until smooth.
Add in you eggs, vanilla and butter and beat until combined.
Mix in your powdered sugar and continue to mix.
Mix in your lemon zest then fold in blueberries, reserving about 1/2 cup.
Spread on top of your cake mixture in pan and sprinkle with remaining blueberries.
Bake for about 40-50 minutes or until center is set but still gooey.
Remove from oven and let cool.
Sprinkle with powdered sugar if desired.
The calories shown are based on the cake being cut into 16 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**