For the Brownies:
- 1 cup (226g) unsalted butter, melted and slightly cooled
- 2 tablespoons vegetable oil
- 1¼ cups (250g) granulated sugar
- 1 cup (200g) light brown sugar, packed
- 4 large eggs, at room temperature
- 1 teaspoon pure vanilla extract
- ½ teaspoon peppermint extract
- 1 cup (125g) all-purpose flour
- 1 cup (100g) unsweetened cocoa powder
- ¾ teaspoon kosher salt
- ½ teaspoon baking powder
- 1½ cups (270g) semi-sweet chocolate chips
- 1 cup crushed peppermint candy canes
For the Peppermint Frosting:
- 1 cup (226g) unsalted butter, softened
- 3 cups (360g) powdered sugar
- 3–5 tablespoons heavy whipping cream
- ¼ teaspoon peppermint extract (optional)
- 1 cup crushed peppermint candy canes