Chocolate Porter Brownies

Name: Chocolate Porter Brownies
Prep time: 10 min
Cook time: 45 min
Total time: 45 min
Yield: 18 pieces
Ingredients: 120 g porter; 150 g dark chocolate (70% cocoa solids); 150 g milk chocolate; 225 g unsalted butter; 240 g sugar; 105 g dark brown sugar; 3 large eggs; 150 g plain flour; 3 Tbsp cocoa powder; 1 tsp baking powder; ½ tsp fine sea salt; 1 tsp natural vanilla extract