1/2 cup white sugar
3 eggs
2 teaspoons vanilla extract
2 teaspoons orange zest
1 teaspoon lemon juice
1/2 teaspoon white vinegar
Melt 1 cup of confectioners' sugar in a large bowl over simmering water until smooth. Add eggs and vanilla; continue to stir until all ingredients are thoroughly combined. Pour egg mixture into batter-filled muffin tin; sprinkle top generously with lemon juice and vinegar.
Bake in preheated oven for 21 min, or until a toothpick inserted into center of a muffin comes out clean. Serve warm.