Step 1

Prepare a 12-cup Bundt pan according to the cake mix package directions. Bake the Devil's food cake according to the package directions. Let cool completely.

Step 2

Combine the softened butter and marshmallow creme in a large bowl and beat with an electric mixer until smooth and well combined. Add the confectioners' sugar and 1 tablespoon cream and beat until fluffy, about 3 minutes. Put the marshmallow creme mixture into a piping bag fitted with a long thin round tip.

Step 3

Flip the cake so it is flat-side up and make 12 evenly-spaced holes in the bottom of the cake using a skewer, pressing only halfway down into the cake and wiggling the skewer slightly to widen the holes until they are each about 1 inch wide. Insert the piping tip in each of the hollowed-out holes and pipe in some marshmallow mixture until it starts to ooze out the top of the hole, reserving about 1/4 cup frosting for decorating the top of the cake. Flip the cake flat-side down onto a cake stand or serving platter.

Step 4

Put the chocolate chips in a small heatproof bowl. Bring the remaining 1/3 cup cream to a boil in a small saucepan, then pour over the chips. Stir until the chips are melted, then stir in the remaining 2 tablespoons butter. Spoon over the cake and let cool until set, about 30 minutes. Pipe connecting loops over the top of the cake with the remaining frosting in the piping bag. Serve immediately or cover and refrigerate for up to 2 days.