Step 1
Whisk 3/4 cup sugar egg yolks and 1 tablespoon lemon zest together in a saucepan over medium heat. Cook until sugar dissolves and mixture is light in color about 3 minutes. Stir in 2/3 cup lemon juice and 3 tablespoons butter. Cook whisking constantly until lemon curd coats the back of a spoon about 5 minutes. Remove from heat; cover and let cool.
Step 2
Preheat oven to 350 degrees F (175 degrees C). Coat two 9x13-inch baking pans with cooking spray and dust each with 1 teaspoon flour.
Step 3
Place 1 cup butter in a microwave-safe bowl; heat in the microwave until melted 2 to 3 minutes. Mix together with graham cracker crumbs and 1/2 cup sugar. Press the crust into the bottom of 1 prepared pan.
Step 4
Bake in the preheated oven until slightly browned about 10 minutes. Leave oven on.
Step 5
Beat cake mix water 3 eggs vegetable oil and 2 tablespoons lemon juice together in a bowl using an electric mixer until smooth. Mix in sour cream; fold in blueberries blackberries and raspberries. Pour 1/2 the batter on top of the crust; pour the rest into the second prepared pan.
Step 6
Bake the batter-filled pan in the preheated oven until a toothpick inserted into the center comes out clean 15 to 20 minutes. Let cool.
Step 7
Beat cream cheese in a bowl with an electric mixer until fluffy. Beat in condensed milk until smooth and fluffy. Add lime juice and zest; mix well. Fold in whipped topping.
Step 8
Scatter dollops of lemon curd over every few inches of the crusted cake. Spread half the cream cheese mixture over the lemon curd. Flip the second cake onto a cake rack; gently place on top of the cheese layer. Smooth the remaining cream cheese mixture on top.
Step 9
Melt chocolate chips in a microwave-safe bowl in 15-second intervals stirring after each melting 1 to 3 minutes. Drizzle on top of the cake. Cover cake; refrigerate until chocolate and cheese layer are set about 3 hours.