For the mint chocolate buttercream frosting:
- 3 sticks butter (unsalted), softened
- 2 pounds confectioners sugar, sifted
- pinch sea salt, fine grain
- 2 teaspoons vanilla extract
- 1 teaspoon peppermint extract
- 5 oz chocolate (bittersweet), melted and cooled
- 4-6 Tablespoons cream, heavy