• Heat the oven to 325°F. Grease and flour a 9-by-13-inch baking pan or spray it with baking spray.
  Butter and flour or baking spray
• In a mixing bowl with an electric mixer on low, combine the cake mix with the beaten egg and the softened butter until the mixture begins to clump together.
  1 box yellow cake mix | 1 large egg | 1/2 cup butter
• Press the crumb mixture into the pan, patting as evenly as possible.

Prepare the Filling

• In a mixing bowl with an electric mixer, beat the softened cream cheese until it is smooth and creamy.
  8 ounces cream cheese
• Add the confectioners' sugar to the cream cheese and beat until blended. Beat the 3 remaining eggs and the vanilla to make a smooth batter.
  16 ounces confectioners' sugar | 3 large eggs | 1/2 tsp vanilla extract
• Spread the cream cheese mixture over the crumb layer.
• Bake for 35 to 45 minutes or until set and lightly browned.