1 tablespoon extra-virgin olive oil, plus more for coating baking dish and drizzling
2 ounces pancetta or slab bacon, cut into 1/2-inch dice
1 medium onion, coarsely chopped
3 cloves garlic, peeled and smashed
1-1/2 cups canned white beans, preferably cannellini, drained and rinsed
2 leafy sprigs fresh rosemary
1 bay leaf
1 cup water, or as needed
Kosher salt and freshly ground black pepper, to taste
1 14.5-ounce can tomatoes, coarsely chopped, with juice
1/4 cup dried bread crumbs
1/3 cup freshly grated Parmesan cheese
Preheat the oven to 350°. Coat a large gratin pan or baking dish with olive oil.
In a heavy saucepan over medium heat, combine 1 tablespoon olive oil and pancetta or bacon. Cook, stirring frequently, until the meat begins to render its fat, about 5 minutes. Add onion and garlic, stir to coat, and saut