Instructions

1. Prepare the chocolate crumb: Preheat the oven to 300 degrees.  Prepare a sheet pan with either parchment or a Silpat liner.
2. Combine the dry ingredients in a mixer with the paddle attachment on low. Slowly add in the butter and mix until the mixture is fairly evenly moistened. Spread out onto your pan in an even layer. Bake for about 15 minutes. Pull out from the oven and let it cool.
3. Prepare the Ovaltine caramel: Measure all ingredients beforehand and have them ready, because this recipe moves quickly. Make a dry caramel: In a heavy-bottomed medium saucepan, cook ¼ cup of the sugar over medium-high heat. As soon as the sugar starts to melt, use a heat-resistant spatula to move it constantly around the pan—you want it all to melt and caramelize evenly to a gorgeous amber color. Once the first amount of sugar has taken on color, add the second ¼ cup sugar to the existing caramel in the pan, repeating the previous steps—cook and stir, cook and stir, until the mixture is once again a gorgeous amber color.
4. Remove pan from heat and stir in the unsalted butter until melted. Next, carefully and slowly stream in the heavy cream, whisking all the while. The mixture will sputter and bubble and produce a ton of steam so watch your hands.
5. Add chocolate chips and stir until melted. Finally, add in Ovaltine, cocoa powder, and salt and whisk until smooth.
6. Transfer caramel to an airtight container and chill for at least an hour, or until thick and glossy, before assembling the cake.
7. Make the cake: Place rack in the upper third of the oven and preheat oven to 350 degrees F. Grease and flour two 9-inch round cake pans and set aside. (Grease and flour a sheet pan or tube pan or line muffin tin with cupcake papers if using.) 
8. In a large bowl stir together sugar, flour, cocoa, baking soda, baking powder, and salt.
9. In a large measuring cup whisk together eggs, buttermilk, coffee, oil, and vanilla.
10. Whisk the wet ingredients into the dry until smooth and flossy, about 2 minutes. Batter will be thin – that’s right.
11. Divide batter between the prepared pans.
12. Bake for 30-35 minutes (18 minutes or so for cupcakes) (35-45 minutes for a bundt cake) or until a skewer inserted into the center of the cake comes out clean or with just a few moist crumbs. Remove from the oven and allow to cool for 10 minutes in the pan before running a butterknife around the edges and inverting onto a wire rack to cool completely.
13. Make the frosting: Cream together butter, cocoa powder and salt. Butter mixture will be very thick. Turn off the mixer, scrape down the sides of the bowl.
14. Add powdered sugar. Turn mixer on low and mix in powdered sugar while adding milk and vanilla extract. As the sugar incorporates, raise the speed of the mixer to beat the frosting. Beat until smooth, about 1 minute.
15. In a 2 cup measuring glass, stir together heavy cream and Ovaltine. Turn mixer speed to medium and pour half of the cream mixture into frosting in a slow, steady stream. Stop the mister scrape down the sides of the bowl. Add remaining cream mixture or until you’ve reached your desired consistency. Beat until soft and creamy, about 1 minute.
16. Assemble the cake by placing one cake circle on your plate. Top with a thin layer of frosting, a thicker layer of the Ovaltine caramel, and most or all of the crumb. Place the second cake circle on top, and frost with the rest of the frosting.