Make the Pudding

In a small bowl, using a spoon, combine the cornstarch and the 3 tablespoons of cold water until smooth. It will be thick and tacky at first. Set aside.

Boil 2 cups of water (you can do this in a microwave safe bowl or measuring cup as well).

Over low heat on the stovetop, place the cocoa powder in a pan and pour in the boiling hot water. Whisk to combine.

Add the sugar and the chocolate chips, continue whisking to combine.

Whisk the cornstarch water mixture into the pan with the chocolate water mixture. Continue whisking. Add the salt and bring to a boil, whisking the entire time. You should see it thickening. If not, increase your heat slightly but be careful not to burn. Let it boil for about a minute, whisking the entire time.

Remove the pan from the heat and whisk in the vanilla and butter or vegan baking stick.

Leave the pan on a cutting board on the counter, whisking periodically until the pudding has cooled significantly.

Then transfer to a heat safe bowl and refrigerate.

You want the pudding thick and cool when you assemble the cake. Make sure the pudding is made ahead of time and is cold from being in the fridge.

Make the Cake

Preheat the oven to 350 degrees. Grease two 8 inch round cake pans with vegetable oil, line bottoms with parchment paper and then grease the parchment paper with vegetable oil as well.

Whisk the gluten free flour, sugar, cocoa powders, baking powder, baking soda and salt in a large bowl until combined and lump free.

Measure out one cup of milk of choice into a measuring cup. Add one tablespoon of white vinegar into the mix and stir with a spoon. Let it sit for 5-10 min and stir again. It should look slightly chunky. That’s normal.

In a separate small bowl, combine the cornstarch and 6 tablespoons of water and mix together with a spoon until thin and watery. It will be thick and tacky at first. Set aside.

Make a well in the center of the dry ingredients. Add the cornstarch water mixture, milk and vinegar mixture, warm water, oil and vanilla. Whisk until smooth. If it starts to get too thick, use a spatula to mix the rest.

Divide the batter evenly between the two greased cake pans.

Bake the cakes for about 47-50 min in the center rack of the oven or until the cakes spring back at you when carefully touched.

Let cool completely in the cake pans. Turn out from pans, and place on cooling racks.

Once they're cool, use a cake knife cut a thin layer off the tops of each layer to make the cakes level and flat on top.

Take the extra cake pieces and cut them into tiny crumbs. Set aside.

Make the Chocolate Frosting

In the large bowl of an electric mixer or using a hand held mixer, beat the butter or vegan baking stick until smooth and creamy. About 2 minutes.

With the mixer on very low speed, slowly add in the confectioners' sugar.

With the mixer on low speed still, add in the cocoa powders.

Add in the vanilla and beat until combined.

While the mixer is on, slowly add in the water a little at a time until you get the desired consistency. You may not need to use all the water.

Assembling the Cake

Place one layer of cake on the bottom of a cake plate/stand. Place some of the frosting in a pastry bag and pipe a ring around the top edge of the cake. This is to keep the pudding from oozing out.

Scoop about ¾ of the pudding into the center of the frosting ring.

Put the second cake layer on top, bottom side up so the top is nice and flat.

Use an icing spatula to frost a thin layer of the fudge frosting on the top of the cake and a thin layer on the sides. This is our crumb layer so the pudding doesn't ooze out.

Pop the entire cake in the fridge uncovered for 15-20 minutes. This will make it more stable to work with.

Take the cake out of the fridge and continue to frost. First frost the sides again and this time immediately press the chocolate cake crumbs into the wet frosting so they stick.

Frost the top of the cake. Press the crumbs into the top as well.

If desired, pipe extra frosting swirls around the top of the cake.

If not serving the cake right away, chill the cake again and take the cake out 15-20 min prior to serving.