4 1/2 cups all-purpose flour
1 teaspoon baking powder
3/4 teaspoon baking soda
1 teaspoon salt
1 cup vegetable oil
8 eggs
1 1/2 teaspoons vanilla extract
1/2 teaspoon lemon extract
1 cup milk
1 egg yolk (optional)
1 teaspoon lemon zest
Preheat oven to 375 degrees F (190 degrees C). Grease and flour two 8 inch round muffin cups.
In a large bowl, mix the flour, baking powder, baking soda, and salt. Beat in the oil, eggs, vanilla extract, lemon extract, milk, and egg yolk. Stir thoroughly until well blended. Pour batter into prepared muffin cups.
Bake in the preheated oven for 20 to 24 minutes, or until a toothpick inserted into the center of a muffin comes out clean. Allow to cool completely.