Grease the inside of a 4 Litre cast iron Dutch Oven with shortening. Next, prepare your favourite boxed chocolate cake mix, and pour the batter into the Dutch Oven.
For the lava, combine 1 cup brown sugar, 1 cup white sugar, and 2/3 cup cocoa powder in a bowl. Sprinkle the cocoa sugar mixture on top of your cake batter. It's going to look like there is way too much dry powder, but trust me, it will be fine. Pour 2 1/4 cups very hot black coffee (or water) over the top of the cocoa sugar mixture. Place your lid on the Dutch Oven.
Using the Baking technique, with 8 charcoal briquettes on the bottom, and 16 charcoal briquettes on the top around the edge.
Allow your chocolate lava cake to bake for 55 minutes.
At the end of the 55 minutes, remove the remaining charcoal and ash from the lid of your Dutch Oven. Remove the Dutch Oven from the heat source, and allow it to stand for 10 minutes before serving.
Serve your Dutch Oven Chocolate Lava Cake with Vanilla Ice Cream or whipped cream.