Preheat oven to 350 degrees. Spray a 9 x 13 inch cake pan with nonstick spray. Mix in a large bowl the cake mix, butter, and 1 egg. Mixture will be dense. Pat mixture into the bottom of your cake pan. In a separate bowl, mix cream cheese, 2 eggs, and sugar. Pour the mixture over the cake layer. Bake for 33 - 35 minutes or until golden brown. Cut out with heart shapes once cool if desired.