1/2 cup unsalted butter, melted
1 cup granulated sugar
2 large eggs
2 teaspoons vanilla extract
1/2 cup all-purpose flour
1/3 cup unsweetened cocoa powder
1/4 teaspoon salt
1/4 teaspoon baking soda
2/3 cup chocolate chips

peppermint pattie layer
2 cups powdered sugar
1 1/2 tablespoons unsalted butter, softened
3 tablespoons evaporated milk
1/4 teaspoon vegetable oil
1/4 teaspoon vanilla extract
1/4 teaspoon peppermint extract

ganache
3.5 ounces dark chocolate, chopped
2.5 tablespoons heavy cream