Mint Chocolate Brown Sugar Bars

I had such a great result with these Chewy Toffee Bars from Food Network's Jamie Deen earlier this fall that I wanted to make a mint version for the holidays. They come together so quickly, so they're perfect for this time of year.

Ingredients 
1 1/2 sticks (12 tablespoons) unsalted butter 
2 1/4 cups light brown sugar 
2 cups all-purpose flour 
2 teaspoons baking powder 
Pinch salt 
2 large eggs 
2 teaspoons pure vanilla extract 
1 cup mint chocolate chips 

Instructions
Preheat the oven to 350 degrees F. Adjust the racks to the center of the oven. Spray an 8-by-8-inch baking pan with nonstick spray. 
Melt the butter in a medium saucepan and stir in the brown sugar until melted together. Let cool for 5 minutes. 
While the mixture is cooling, whisk together the flour, baking powder and salt in a medium bowl. 
Stir in the eggs, one at a time, and vanilla extract into the cooled sugar and butter mixture. Add the dry ingredients into the saucepan until combined. Fold in the mint chocolate chips. 
Spread the mixture into the prepared pan. Bake until golden brown and a toothpick inserted into the center comes out clean, about 45 minutes. Cool for 15 minutes before slicing into squares. 
Yields 16 servings