Melt 2 tablespoons of your butter. Add anchovies and capers with brine. Saut�, you want the anchovies to start to brown and the capers to become fragrant. Add tomato paste and cook over a low heat for about 15 minutes. Take the mixture off the heat and let it cool. Pour it over the rest of your room-temperature butter, along with balsamic vinegar and mix until combined |