2 eggs
1 cup milk
1 1/2 cups white sugar
1 egg yolk, beaten
1 cup butter
1 teaspoon vanilla extract
1 teaspoon lemon zest
1 teaspoon ground cinnamon
In a small bowl, mix egg yolk, sugar, egg yolk, butter, vanilla, lemon zest and cinnamon. stir until smooth.
Place filled muffin in prepared pans. Spread 1/2 cup of batter on top of each muffin. Top with a slice of the quarter-inch pastry for eyeletting. Place muffins on 8 9 inch muffin pans.
Bake at 375 degrees F (190 degrees C) for 25 to 35 minutes or until center of each muffin is almost set. Cool immediately before removing from pans.