My neighbor Dorothy brought this to our potluck in 1978 and I begged her for the recipe for two years before she finally shared it.

For picky eaters: If mushrooms are a hard no for someone at your table, you can cut the mushrooms in very small pieces so they mostly melt into the sauce, or use just one package instead of two. You can also swap the diced tomatoes for crushed tomatoes if your kids don’t like chunks.

For extra flavor: Stir 1 teaspoon dried Italian seasoning or a clove of minced garlic into the tomato and soup mixture before pouring it over the chicken. A splash (2–3 tablespoons) of dry white wine, if you have it, can also be added to the sauce for a slightly more traditional Marengo-style flavor without complicating the recipe.

Protein swaps: Bone-in, skin-on drumsticks work well in place of thighs; just use the same total weight and check for doneness. Boneless, skinless thighs will cook a bit faster and won’t brown quite the same, but they stay very tender—start checking them about 10–15 minutes earlier.

Food safety tips: Always wash your hands, cutting board, and any utensils that touch raw chicken with hot, soapy water before using them with other foods. Make sure the chicken reaches at least 165°F (74°C) in the thickest part near the bone; use an instant-read thermometer if you have one. Don’t leave the finished casserole at room temperature for more than 2 hours (or 1 hour if it’s very warm in your kitchen). Refrigerate leftovers promptly in shallow containers and use within 3–4 days, reheating until steaming hot all the way through before serving.

Freezing: This casserole freezes well; cool completely, then freeze in airtight containers for up to 3 months. Thaw overnight in the fridge before reheating, adding a splash of water or broth if the sauce seems too thick.