13tablespoonsunsalted butter, melted until browned
1 1/2teaspoonsvanilla extract
1cupdark brown sugar
2large eggs, at room temperature
2cups+ 2 tablespoons all-purpose flour
For the Bourbon Buttercream:
1stick (4 ounces) unsalted butter, VERY soft
1and 3/4 cups powdered sugar, to start; you may need more
For the Brown Butter Sugar Cookie Bars:
Preheat oven to 325 degrees (F). Line a 9x13 inch baking pan with parchment, and lightly spray with cooking spray. Set aside.
Place butter in a large, heavy bottomed pan over medium-low heat and melt. Once the bar has completely liquified, continue to cook it, stirring almost constantly, until it bubbles up and takes on a nutty aroma. Remove from heat at once.
Add vanilla and sugars and mix well to combine. Add in eggs - quickly - and beat until they're fully incorporated in the batter.
Add in the flour and salt and using a rubber spatula fold the flour into the batter until just combined - don't over mix!
Pour your batter - it will be thick - into the prepared pan, and place it in the oven to bake for 22-25 minutes, or until the edges have set and the center doesn't wobble. Allow bars to cool in the pan for 5 minutes before lifting up the tabs of the parchment paper and transferring them to a cooling wrack to cool completely.
In the meantime, make your bourbon buttercream!
Place the softened butter in a large bowl OR the body of your stand mixer fitted with the paddle attachment. Beat on medium-speed until light and fluffy, then add your sugar - a little bit at a time. The mixture will look pasty and dry, but don't worry! Once you add your liquid it fluffs up!
Add the bourbon, then the cream, cinnamon, and the finally the salt; beat on high for one minute. If the buttercream appears too soft, add a small bit more confectioners' sugar. If it appears too dry, add a small dash of cream (or bourbon). Once the buttercream has reached your desired texture and taste (I always add a dash more bourbon…), you may store it on the counter (as long as it's in a cool room) until needed. Or plop it in the fridge until needed, just be sure to give it a few minutes to come to room temperature before spreading.
Spread buttercream over cooled cookie bars, cut into squares, and serve! I added gold sprinkles to the tops of mine, but I think the decorating options for these bars are endless!