Heirloom Tomato and Sweet Onion Spaghetti

I was flipping through my favorite cookbooks, looking for tomato-inspiration, when I came across a recipe for Spaghetti with Heirloom Tomatoes, Basil and Bottarga Breadcrumbs in Sunday Suppers at Lucques. While I wasn’t looking for anything as complicated as making homemade breadcrumbs flavored with cured tuna roe on this particular evening, the other flavors in the recipe sounded just right, so I made a few quick modifications and tried it. It was good, but not mind-blowing. But I loved the idea of the dish, and there were elements that were really strong – I loved the mellow sweetness of the onions melding with the tangy-sweet tomato, the way the rosemary fried in olive oil seemed to perfume the whole dish, and the process of cooking the spaghetti in the sauce so it would soak it up. It just needed more body and more salt. So I kept trying the recipe, adding a spoonful of capers here, toning down the chile heat, and finally, the move that sealed the deal, stirring in a generous spoonful of mascarpone cheese, which transformed the sauce into something silky and luxurious that coated every noodle.