I am in the process of converting my recipes from conventional to gluten free/vegan which is HARD (especially vanilla) so I have some questions. Below is my recipe and exactly how I’m mixing and baking. Right now the first thing I’m changing is the flour from regular to gluten free and once I get that master for this recipe I’ll change the other dairy/egg ingredients to vegan one at a time. I’m using America’s Test Kitchen gluten free flour blend recipe for the flour in these cupcakes. 

GLUTEN FREE VANILLA CUPCAKES

4 oz melted butter

7 oz. cane sugar

2 tsp. vanilla extract

1 TBLS. apple cider vinegar

2.75 oz. whole fat sour cream

2.75 oz. 2% milk

7.25 oz. ATK gluten free flour blend

1/2 + 1/8 tsp. baking soda

1/2 tsp. xantham gum

1/2 tsp. sea salt

2 egg whites whipped to soft peak stage

1. First I sift together the flour, soda, salt and xantham gum in the bowl of my stand mixer.

2. Next I whisk together the melted butter, sugar, vanilla, ACV, sour cream and milk. 

3. Thirdly, I pour the wet ingredients into the dry and beat for 5 mins in my stand mixer. (I have read this is how you get gluten free cakes super fluffy and it worked amazing for my gluten free chocolate cupcakes. They were as fluffy and soft as a cake mix!)

4. Lastly I fold in the soft peak egg whites in 3 additions gently with a spatula until combined.

5. Makes 12 cupcakes and I bake center rack of oven 325 degrees F for 25-28 mins until toothpick comes out clean or almost clean. I bake at 325 because I’ve read gluten free cakes should be baked lower and longer.

They look AMAZING when they come out of the oven but with in a couple minutes fall to a flat top and shrink in size all the way around. The flavor is fantastic and the moisture level and crumb is so perfect and soft, but can anyone tell me why they shrink so bad and if something in my recipe is off ratio or ingredient-wise?

12 cupcakes should bake in about  half that time

I like a dome on my cupcakes, so I start my oven at 400 and lower it to 350 when the cupcakes go in.  This is for cupcakes with gluten.  Not sure if it works the same way with gluten free, but give it a try.  I usually place a baking sheet in the rack under the rack that contains the cupcakes to try to stop the bottoms from burning.  I agree that vanilla is a tricky thing!