Heat oven to 350℉/177℃.
Spray three 8-inch round cake pans with baking spray. Set aside
Melt chocolate in microwave safe bowl on 15 second intervals, stirring after each, until smooth. Set aside.
In a large bowl, whisk together flour, sugar, baking powder, salt, and baking soda. Set aside.
In a medium bowl, whisk together eggs, vegetable oil, milk, vanilla extract and peppermint oil.
Pour wet ingredients into dry ingredients.
Whisk until smooth, 1-2 minutes.
Fold in chocolate.
Pour into prepared pans.
Bake for 20-25 minutes until cakes test done.