Tangerine sponge/custard cake

This recipe originally comes from here but I have made a few adjustments.

• 1 tbs butter-softened
• 1 tbs. minced or grated tangerine peel
• 3 egg yolks
• 3 Tbsp. flour
• 1/2 tsp. vanilla
• 1/2 cup tangerine juice
• 2/3 cup of milk
• 3 egg whites
• 1/8 tsp cream of tartar
• 1/3 cup sugar

Preheat the oven to 350. Grease a souffle dish. 

Start by mixing the butter and tangerine peel. Then mix in the flour, vanilla, and egg yolk to make a paste. Slowly mix in the tangerine juice and then the milk until everything is smooth. 

Beat the egg whites and cream of tartar until stiff peaks. Then slowly beat in the sugar. 

Fold the egg white mixture into the tangerine mixture. Carefully and slowly pour the mixture into the prepared souffle dish. Place the dish in a water bath and bake for about 40 minutes. Chill for at least 1 hour. 

As it cooks the mixture separates into a cake layer and a custard layer. 

This dish should work just as well with most citrus fruits. Lemons and limes will be more tart but oranges, grapefruits etc. should work out to a similar flavor.