Archimedes's Circumscribing Pi-Cake

Step 4: Prepare the cakes

After the cakes have cooled completely, you can prepare each to be filled with pie crust and filling. Make sure this is done before you bake your pie crusts.

1. Remove the cakes from the pan. No need to level the cakes if they're a bit domed. The extra height helps. 
2. Flip each upside down. Using a knife, score a circle about a half inch deep about half an inch smaller than the cake on all sides.
3. Now start digging. I preferred to do this with my hands, as I was able to gentle scrape the cake innards out without marring the whole cake. 
4. You'll want to pull out cake scraps until you have a nice half sphere that is the perfect resting place for a French silk pie.
5. Reserve the cake scraps and combine them with leftover French silk filling for a yummy mush. Wait. What? I didn't do that.