Brownies with browned butter buttercream

I found this treasure of a recipe from Mel's Kitchen Cafe food blog. I was so curious about the browned butter element I just had to try it and find out for myself. I doubted myself the whole time I was browning the butter. I was afraid I was going to burn it, but I kept the heat low and it turned out perfect. The browned butter frosting gave it such an interesting toffee flavor, with the chewiness of a decadent brownie. I thoroughly recommend this recipe.
 
Brownies:
1/2 cup (1 stick) butter
6 ounces unsweetened chocolate
2 cups sugar
4 large eggs
1/4 teaspoon salt
1 cup all-purpose flour
1 teaspoon pure vanilla extract
Browned Butter Frosting:
1/2 cup (1 stick) butter
2 cups powdered sugar
1/4 cup heavy cream
1 teaspoon pure vanilla extract
Glaze:
3 tablespoons butter
4 ounces bittersweet or semisweet chocolate, chopped ( I used dark chocolate chocolate chips) Preheat the oven to 300 degrees F. Lightly grease a 9X13-inch pan with nonstick cooking spray and cut parchment paper (I used wax paper because I didn't have parchment paper) to fit the bottom of the pan. Lightly grease the parchment paper. Set the pan aside.
For the brownies, in a small saucepan, melt the butter and chocolate, stirring until smooth. Set aside to cool slightly. In a large bowl, combine the sugar, eggs and salt. Mix with a hand-held mixer or in the bowl of a stand mixer for 3-4 minutes, until the mixture has lightened in color and is very thick. Fold in the warm (not hot!) chocolate/butter mixture. Stir in the flour and vanilla extract. Mix until well combined. Pour the batter into the prepared pan, smoothing evenly.
Bake the brownies for 25-30 minutes until the sides pull away from the pan just slightly. Remove the brownies from the oven and cool completely on a wire rack (about 1 1/2 hours).
For the browned butter frosting, place the stick of butter in a small saucepan and set it over low heat. It is best to not use a non-stick or dark coated pan in this step because it will be difficult to tell when the butter has turned brown. Let the butter melt over low heat and turn a caramel brown color, about 15 minutes. Watch carefully so the butter doesn’t burn. Once it has turned a nice medium-brown color, remove it from the heat. Pour the butter into a medium bowl. Immediately add the powdered sugar, heavy cream and vanilla. Mix well with an electric mixer until the frosting is smooth and thick.
Spread the frosting over the cooled brownies.
For the glaze, melt the butter and chocolate together in the microwave or on the stove top until it is smooth. Pour the warm glaze over the frosted brownies and spread with a knife. Chill the brownies until the glaze is set and the brownies are chilled through, about 1-2 hours. The brownies taste best cold.