Place the beans in a food processor and blend until pureed and creamy. Add in the garlic powder, salt and pepper, then continue to blend while streaming in 2 to 3 tablespoons of the brown butter. Stream in the ice water and blend. The dip should be smooth and creamy. Add in the sage leaves, reserving 1 for the top for garnish. Spoon the dip into a bowl. Drizzle with the remaining brown butter right before serving. Top with the reserved sage leaf.