I used a couple pints of grape tomatoes for this sauce, along with olives, capers and of course anchovies. I like to cook with grape tomotoes because they're intensely flavored and don't require chopping. They simply burst as they cook. When I added several cups of the starchy pasta water the sauce took on an almost creamy consistency. I boiled the spaghetti for only a few minutes to soften it before adding it to the sauce. It therefore absorbed the complexity of flavors as it cooked. I tossed in the crab just before serving.