I've been drooling over these for a week now. I found the recipe over on Culinary in the Desert. I made a half batch and baked them in an 11" x 7" pan. I probably should have used a 13" x 9" pan to stay true to the recipe. These puffed up much more than I expected, but the icing didn't all sink down into the center, so it worked well. I'll likely make these again another day.
Butterscotch Brownies With Brown Sugar Butter Icing
For the batter:
3 cups all-purpose flour
1 tablespoon baking powder
1 teaspoon salt
16 tablespoons (1 cup or 2 sticks) unsalted butter, softened
3 cups packed brown sugar
4 large eggs
1 tablespoon vanilla
For the icing:
16 tablespoons (1 cup or 2 sticks) unsalted butter
2 cups packed brown sugar
heaping 1/4 teaspoon salt
4 cups sifted confectioners' sugar
1/3 cup half-and-half
1 tablespoon vanilla
To prepare the batter:
Preheat the oven to 350 degrees.
In a medium bowl, whisk together flour, baking powder and salt.
In a large mixing bowl, beat together butter and sugar until smooth and creamy. Beat in the eggs, one at a time, mixing until well combined after each. Mix in vanilla. Add dry ingredients and mix just until combined.
Pour mixture into a 13" x 18" half-sheet pan coated with nonstick spray, smoothing the top with an off-set spatula. Place pan into the oven and bake until the bars are set and slightly puffed, about 25 to 30 minutes. Remove from the oven and allow to cool completely.
To prepare the icing:
In a medium saucepan, melt butter, brown sugar and salt over medium heat. As soon as the mixture is lightly bubbling, reduce heat to medium-low and cook, stirring, for 2 minutes. Remove from the heat and set aside.
In a large mixing bowl, beat together confectioners' sugar, half-and-half and vanilla until smooth. Pour in the melted butter mixture and beat until combined. Immediately spread icing over brownies and allow to sit for 30 minutes before cutting into squares.
Makes about 30 brownies (though you could get away with cutting them smaller as they are fairly rich).