Many recipes say to "brown" the onions for that deep sweet flavor, but many others (Kris Dhillon for example) say just make a "base sauce" by simmering onions, cabbage, carrots with water on low heat for an hour, then blending, but that method doesn't brown the onions at all. Help me understand: what's the advantage of slow-simmered onion "base" if it never browns? Don't we want to brown? Is it possible to combine methods somehow, brown AND simmer? How?