Preheat your oven to 350°F (175°C). Line an 8-inch square baking pan with parchment paper and set aside.
In a large bowl, mix together the melted butter, granulated sugar, cocoa powder, and salt until well combined.
Stir in the peppermint extract and then beat in the eggs, one at a time, until the mixture is smooth and shiny.
Add the baking powder and flour to the mixture, stirring just until combined. Be careful not to overmix.
Fold in the chocolate chips and crushed peppermint candies gently.
Spread the batter evenly into the prepared baking pan.
Bake for 25 minutes or until a toothpick inserted into the center comes out with just a few moist crumbs attached.
Remove the brownies from the oven and allow them to cool in the pan on a wire rack before cutting into squares.