Step #1 

• Use large pieces of chocolate cake (round layers or from a sheet
  cake) grate over a parchment lined tray using a donut screen.

Step #2

• Place in a 350° oven for approximately 6-8 minutes, tossing
  crumbs every 2-3 minutes to ensure even baking throughout.
  Remove tray from oven.

Step #3

• Add mini chocolate chips to crumbs, combine evenly and place
  back in oven for an additional 1-2 minutes to slightly melt the
  chips. Pull from oven and mix thoroughly.

Step #4

• Cool topping and store in cabinet, covered with a tray liner.