Preheat oven to 350F/180C/gas mark 4. Line 18 cupcake tins with liners.
Separate the eggs.
Beat egg whites until stiff peaks form. Set aside.
In a medium bowl, whisk flour with baking powder, baking soda, and psyllium husk powder (if using).
In a mixing bowl (or the bowl of a stand mixer), beat egg yolks, agave syrup, coconut milk, oil, and vanilla until smooth.
Add flour mixture and beat just until no lumps remain. Fold in egg whites using a spatula until mixed in completely.
Scoop batter into prepared pans, about 2/3 full. Place on center rack. Bake 10 minutes, then rotate pans. Bake another 10 minutes, or until tops spring back and a toothpick comes out clean.
Cool completely on wire racks before frosting.
Fudgy frosting
Place coconut sugar in blender and blend on high for one minute or until a fine powder.
Place sweet potato and stevia in food processor fitted with S-blade. Process until smooth.
In a heavy-bottomed saucepan, place remaining ingredients and stir over low-medium heat until melted and smooth. Scrape into food processor. Blend until very smooth.
For thick fudgy frosting, immediately spread on cupcakes. For pipe-able buttercream style frosting, refrigerate until cold. Then beat until fluffy. Use a large piping tip to create frosting swirls as shown.
Notes
For best taste, eat the day they are baked. Warm briefly in a microwave on day two. For a two-layer cake, grease two 8-inch cake tins, then divide batter evenly. Bake 35-40 minutes, rotating pans about halfway through the baking time. Cool for 15 minutes in the pans before removing to a wire rack to finish cooling. Adapted from Golden Vanilla Cake or Cupcakes and Chocolate Buttercream Frosting from Naturally Sweet & Gluten-Free by Ricki Heller. There are many, many recipes in this book that could be adapted to The Migraine Relief Plan.