Adjust oven rack to upper-middle position and preheat broiler on high. Arrange the torn pieces of bread in a single layer on a rimmed baking sheet. Broil until browned, about 5 minutes, shaking the pan as necessary for even browning. Remove from oven and set aside.
Meanwhile, in a Dutch oven or large pot over medium-high heat, heat oil until shimmering. Add sausage and onion. Cook, stirring occasionally, until sausage and cooked through and onions are softened, about 5 to 7 minutes.
Stir in garlic, thyme, and red pepper flakes until fragrant. Stir in tomatoes and their juice, 1 can of beans, and wine. Bring to boil, reduce heat, and simmer uncovered until stew thickens and darkens, about 10 to 15 minutes.
Add remaining can of beans to pot. If stew looks too thick, add more wine or water, 1/4 cup at a time until stew reaches desired thickness. Stir until heated through, 3 to 5 minutes.
Season to taste with salt and pepper. Garnish individual portions with chunks of bread and a drizzle of olive oil.
Italian Sausage: Sweet or mild, but you can use hot or spicy if you prefer. To substitute sausage links, brown them in the skillet with the onion, then transfer to a cutting board and chop into small pieces. Return to the pot.
Red onion: Yellow or white onions are fine too.
Thyme: Fresh thyme tastes a lot better than dried here. But, dried works if that's all you have.
Red pepper flakes: Omit if you don't like spicy food. Add more if you do!
White beans: You can use navy beans, great northern beans, Cannelini beans, or whatever beans you have in your pantry. 3 cups cooked beans can be substituted for the 2 cans (that’s about 1 cup dried beans before cooking).
White wine: Choose a dry variety such as Chardonnay. Substitute water or chicken broth if you want to omit the wine.
Yield: This recipe makes 4 (2-cup) servings.
Storage: Store leftovers covered in the refrigerator for up to 4 days.
Make ahead: This stew tastes even better the second day. Make up to 3 days in advance, holding back the bread chunks until serving time.
Freezer: Chill within 2 hours, transfer to a freezer-safe container, label, and freeze for up to 3 months. Thaw overnight in the refrigerator. Toast the bread chunks the day you are serving the stew.
Leafy greens: A handful of kale or spinach adds a pretty green color and extra heartiness to the stew.
Parmesan cheese: A sprinkle of cheese fits right in here.