Preheat the oven to 350 degrees.
In a large bowl, combine the cake mix, sugar, cornstarch, milk, eggs and vanilla.
Whisk together.
Add in the yogurt, flour and salt and mix until there aren’t any lumps.
Divide the cake batter evenly between 2 - 18x13 half sheet baking pans.
Use a spatula to even out the batter so it bakes evenly.
Place in the oven and bake for 13-15 minutes (or until a toothpick comes out cleanly). It will cook fast as the cake is thin, so keep an eye on it.
Remove and let the cake cool to room temperature.
Flip the cake out onto a piece of parchment paper and use a 2” circle cookie cutter to create as many circles as possible. Lay them on a tray and place them into the freezer for at least an hour to chill. The cake will be sticky, so freezing will make it easier to work with.
To make the filling, place the marshmallow creme, butter, powdered sugar, vanilla and heavy cream into a large mixing bowl and beat until the mixture is smooth and creamy. You may need to adjust the amount of cream to make the filling spreadable, but stiff enough to hold its shape.
To assemble, spread a small amount of filling in between to cake circles and gently press them together to create a stack. Repeat until they are all assembled.
To create the coating, place the almond bark and coconut oil in a medium sized bowl and melt in short increments in the microwave until fully melted and smooth.
Use a fork to hold each cake to dip into the coating and make sure all sides are evenly coated.
Set the cake on a clean piece of parchment paper. Repeat until all the cakes have been dipped.
Once the coating has hardened (about 15 minutes), place the chocolate chips in a small bowl and melt in short increments in the microwave, stirring frequently, until the chocolate is fully melted.
Place into a piping bag with a small round tip (K01 shown) and pipe squiggly lines across the tops of the cake to resemble zebra stripes.
Let the cakes harden (about 15-20 minutes) and they are ready to serve!