In a large bowl, sift together 1 ½ cups of all-purpose flour, 1 ½ cups of granulated sugar, ¾ cups of black dark chocolate cocoa powder, 1 ½ tsp of baking powder, 1 ½ tsp of baking soda, and 1 tsp of salt.

In a separate bowl, whisk together 2 large eggs, ¼ cup of vegetable oil, ¾ cup of buttermilk, and 2 tsp of vanilla extract until blended.

Pour the liquid mixture into the dry ingredients and stir until just combined.

Gradually introduce the hot water into the mixture while stirring. The batter will have a thin consistency, but that's perfectly fine. Divide batter evenly into two 9 inch cake pans that you've lined with a circle of parchment paper at the bottom.

Bake your cakes at 350°F (180°C) for 25-32 minutes.

To make the chocolate frosting, put ⅔ cup of black cocoa powder, 2 cups of unsalted butter, 5 cups of powdered sugar, a pinch of salt, 2 tsp of vanilla and ⅓ cup of milk or heavy cream in a large mixing bowl.

Mix your butter first, to soften it and then add the other ingredients. Blend with a stand mixer or hand mixer on a low speed until the ingredients start incorporating, then switch to a high speed. If your chocolate buttercream icing is too thin, add more powdered sugar. If your frosting is too hard and clumped, try adding more milk.

Fully cool your cake on a wire rack before you start decorating. Once the cake is room temperature, I recommend wrapping it with plastic wrap and putting it in the fridge or freezer to ensure it’s completely cold.

Trim your cakes flat with a serrated knife and save the pieces you’ve trimmed off for later.

Put one cake down on a cake board and frost the top of it, then stack the second cake on top.

Next, frost the top and sides of the cakes. I use a piping bag with no tip to get an even thick layer all the way around my entire cake first, then I smooth it with a cake spatula.

You can use whatever color you’d like for the candy melts on top of this cake to make the drip effect. I chose pink for the birthday girl, but green would look great too. Brown would look classic, and red would look volcanic.

Melt your candy melts according to the instructions on the label and then use vegetable oil to thin out the candy melts. Do not use milk or water to thin out your candy melts; it will cause the candy to seize and it won’t be usable. Add vegetable oil one spoonful at a time until you’ve got your desired consistency. Too thin and it will run right off the edge of the cake before it forms a drip and if it’s too thick, it won’t spread enough.

Add stripe of frosting to the bottom border of your cake so you can stick chocolate-covered raisins around the perimeter. (You can use other candy like chocolate malt balls or something else that looks like boulders).

Add some pieces of caramel popcorn onto the bottom layer, and attach them with a drop of chocolate frosting so they stay put.

Crush the trimmed cake pieces you set aside and saved, and add them to the top of your cake in a heap to look like dirt. Add more chocolate-covered raisins for boulders.

Add some extra caramel popcorn to the top of the cake.

Add small plastic toy dinosaurs to the top and sides of the cake.

Add small plastic leaves to the top of the cake; you can buy larger stems of plastic greenery from a dollar store or craft store and trim them down to size.