Preheat oven to 350 degrees.
Lightly grease a 13x9 inch baking pan.
In a large bowl, combine cake mix, 1 egg, &1 stick melted butter, & stir until well blended. Pat mixture into prepared pan & set aside.
In a stand mixer,or witha hand mixer beat the cream cheese until smooth. Add the remaining 2 eggs, & cocoa powder. Lower the speed of mixer, & add powdered sugar. Continue beating until ingredients are well mixed. Slowly add the remaining 1 stick of melted butter, & the vanilla, continuing to beat the mixture until smooth. Stir in nuts with a rubber spatula. Spread filling over cake mixture in pan. Bake 40 -50 minutes. Be careful not to overlook the cake. The center should be still a little gooey when finished baking. Let cake partially cool on a wire rack before cutting into pieces.
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Double chocolate gooey butter cakes recipe