COOKIE EXCHANGE REDUCTION
Pour 12 oz. of Cookie Exchange Milk Stout into a small saucepan and heat until boiling. Reduce heat to a simmer. Let simmer until reduced to ½ cup of liquid. Will take about 20 minutes. Set aside to cool. 

BROWN BUTTER MIXTURE
Cook butter in a medium saucepan over medium heat, stirring often, until butter foams then browns, about 5 to 8 minutes. Transfer brown butter to a medium bowl and let cool slightly. Add egg, brown sugar, salt, and 1/4 cup of Cookie Exchange reduction. Beat until mixture is light and falls back onto itself in a slowly dissolving ribbon, about 3 minutes. Fold in flour. 

BLONDIE
Preheat oven to 350 degrees F. Grease a 13 x 9” baking dish. 
Whisk baking powder, salt, and 2 1/4 cups flour in a medium bowl. 
Using an electric mixer on medium-high speed, beat brown sugar and 1 cup butter in a large bowl until light and fluffy, about 5 minutes. Add eggs one at a time, beating between additions. Mix until pale and fluffy, about 2 minutes. Mix in remaining 1/4 cup Cookie Exchange reduction. 
Reduce speed to low and mix in dry ingredients. Fold in half of pecans. Scrape two-thirds of batter into prepared baking dish. Smooth top, pushing batter to edges. Alternating, dollop brown butter mixture and remaining batter on top. Swirl the top with a spatula. Smooth and sprinkle remaining pecans over batter. 
Bake until the blondie is golden brown and firm (a tester will not come out clean), about 30 to 35 minutes. Let cool before slicing. Serve with ice cream (optional). 
Store tightly wrapped at room temperature.