Preheat the oven to 350 degrees.

In a medium sized bowl, whisk egg yolks with the butter.

In a medium sized bowl, add milk, sour cream, lemon juice and zest. Whisk.

Pour the lemon mixture into the egg yolk mixture and whisk.

In another medium sized bowl, add egg whites. Mix on high speed until they form stiff white peaks. Gently fold this into the lemon mixture.

Spray ramekins with coconut oil. Pour batter into each ramekin.

Fill a baking dish with hot water about 1 inch deep. This will prevent the cakes from cracking. Add the ramekins to this dish.

Bake for 30 minutes and check them. Mine cooked in 30 minutes but readers who have used different gluten free flour blends have needed to cook these a little longer. When done, remove carefully from the oven so you don't spill the hot water.

Cool then dust with powdered sugar, or top with fruit.