Preheat oven to 350 and grease & flour two 8-inch round cake pens. Set aside.

Whisk together flour, baking powder, and salt in a small bowl. Set aside.

In a large bowl, cream together butter and sugar. Beat in eggs and yolks one at a time. Stir in vanilla, essential oil, and food coloring.

Alternately add milk and flour mixture, beating until ingredients are completely incorporated, but don't overmix.

Pour batter into prepared pans.

Bake for 25-30 minutes, or until a toothpick inserted near the center comes out clean.

Cool for 15 minutes in the pans before turning out onto racks to cool completely.