Prepare the chocolate cake according to the package directions, adding espresso powder if using for a deeper chocolate flavor. Bake the cakes in two round cake pans and allow them to cool completely before assembling.

While the cake cools, prepare the caramel filling by mixing the caramel sauce with sweetened condensed milk until smooth and creamy. This creates a rich filling that soaks slightly into the cake layers and adds extra moisture.

In a chilled mixing bowl, whip the heavy cream, powdered sugar, and vanilla extract until soft peaks form. Continue whipping until the frosting becomes fluffy and spreadable, being careful not to overmix.

Place the first cake layer onto a serving plate and spread a generous layer of caramel filling over the top. Add a layer of whipped frosting, then sprinkle with some toffee bits and chocolate chips for added texture.

Place the second cake layer on top and cover the entire cake with the remaining whipped frosting. Smooth the sides and top using a spatula.

Pour chocolate ganache over the top of the cake, allowing some to drip naturally down the sides for a bakery-style look. Drizzle caramel sauce over the ganache, then finish with extra toffee bits and chocolate chips.

Refrigerate the cake for at least 1 hour before slicing so the layers can set properly and the flavors can blend together beautifully.