You are going to love these bars because they are super simple to make and taste like a chewy soft cake with a sweet smooth chocolate filling. They freeze wonderfully, which makes an excellent make-ahead treat.
Preheat oven to 350° F.
Combine the cake mixes, eggs, and oil together in a large bowl. Press two-thirds of the mixture into a large greased cookie sheet. Reserve the remaining cake mixture for later.
Place the sweetened condensed milk, chocolate chips, and butter together in a microwave-safe bowl. Microwave, uncovered until chocolate chips and butter are melted, about one minute and stir until smooth. Pour over your bottom cake layer.
Add the remaining cake mixture on top of the chocolate by teaspoonfuls. Bake for 20-25 minutes or until lightly browned. Cool completely on a wire rack before cutting. So good!
Cover and store leftover bars at room temperature for up to 1 week, or in the freezer in freezer safe bag or container for up to 3 months.
Tip: place between layers of parchment if the container is not wide enough to place in a single layer.