Mint Chocolate Chip Whoopie Pies

Ingredients

• 16 tablespoons (2 sticks) unsalted butter
• 1 1/2 teaspoons salt
• 2 teaspoons peppermint extract
• 1 tablespoon baking powder
• 1 1/2 cups (10 1/2 ounces) sugar
• 3 eggs
• 4 1/2 cups (22.5 ounces) all-purpose flour
• 1 cup (about 8 ounces) milk
• green food coloring, to taste (optional)
• 2 cups chocolate morsels
• 4 cups (24 ounces) chocolate chips
• 2 tablespoons light corn syrup
• 4 tablespoons (1/2 stick) unsalted butter
• 1 1/2 cups (12 ounces) heavy cream
• 1/2 teaspoon peppermint extract