First time making frittatas. I didn't use a recipe. I ssed 6 whole eggs, 6 egg whites, 1/2 minced red and yellow peppers each, 1/2 onion, and salt and pepper. Put them in a muffin pan. They rose and looked fantastic until I took them out. They were like hockey pucks! They taste great put they're not dense at all. They totally deflated.
Did I need dairy? Did I need more yolks?