Birthday Cake Suprise

Here is my beautiful gluten free birthday cake.  I have made this recipe a million times before.  Its a great cake. This time we also splurged and made German buttercream frosting.  It was the best frosting I've ever had.

But it seems that somewhere along the way I screwed up.  We sliced it up after dinner tonight.  I took a great big bite and it turned into a grimace.  It tastes like baking soda.  I choked down about half a slice before scraping off the frosting and leaving the cake behind.  Pat on the other hand decided to eat his whole slice and now tells me that the cake is trying to make him explode.