This oven baked 5-ingredient chicken florentine casserole is the one my husband asked for on his 80th birthday instead of going out to a restaurant. He said nothing else compares to the way his mother used to make it, and this is my careful, simple tribute to that memory. It’s creamy and comforting, with tender chicken tucked into a bed of spinach and topped with a bubbling Parmesan crust. The recipe is pared down to just five basic ingredients, the way a lot of Midwestern church-supper casseroles were in the 60s and 70s, but it still tastes like something you’d be proud to set out for a special family dinner. It’s the kind of dish you pull from the oven in a deep ceramic baking dish, steam rising, and everyone leans in with their plates ready.
This casserole is rich and creamy, so I like to balance it with something simple alongside: buttered egg noodles or mashed potatoes to catch the sauce, a pan of roasted carrots or green beans, and a crisp green salad with a tangy dressing to cut through the richness. Warm dinner rolls or a slice of crusty bread are perfect for wiping the dish clean. For a special occasion like an 80th birthday, I’ll set it out in the center of the table with a big serving spoon and let everyone scoop their own, then finish the meal with a light dessert like fresh fruit or a simple sheet cake.
Oven Baked 5-Ingredient Chicken Florentine CasseroleServings: 6
Ingredients
2 pounds boneless, skinless chicken breast, cut into bite-size pieces
2 (10-ounce) packages frozen chopped spinach, thawed and well drained
2 (10.5-ounce) cans cream of mushroom soup
1 cup sour cream
1 1/2 cups grated Parmesan cheese, divided
1/2 teaspoon kosher salt (optional, to taste)
1/2 teaspoon black pepper (optional, to taste
Nonstick cooking spray or a little butter for greasing the baking dish
Directions
Preheat your oven to 375°F (190°C). Lightly grease a deep 9x13-inch ceramic baking dish with nonstick spray or a little butter so the casserole doesn’t stick.
Prepare the spinach: Place the thawed chopped spinach in a clean kitchen towel or several layers of paper towels and squeeze firmly over the sink to remove as much water as you can. This keeps the casserole from turning watery.
In a medium bowl, stir together the cream of mushroom soup, sour cream, 1 cup of the grated Parmesan cheese, salt, and pepper until smooth and well blended. This will be your creamy Florentine sauce.
Spread the drained spinach evenly over the bottom of the prepared baking dish, breaking up any clumps so it forms a nice, even bed of greens.
Scatter the bite-size pieces of raw chicken evenly over the spinach layer. Try to keep the chicken in a single layer so it cooks through evenly in the oven.
Pour the creamy sauce mixture over the chicken and spinach, using a spatula to spread it out so everything is covered and the sauce seeps down into the layers.
Sprinkle the remaining 1/2 cup grated Parmesan cheese evenly over the top to form the crust that will brown and bubble as it bakes.
Cover the baking dish tightly with foil and place it on the middle rack of the preheated oven. Bake covered for 25 minutes to help the chicken cook through and the spinach finish wilting under the sauce.
Carefully remove the foil (watch for steam), then return the uncovered casserole to the oven. Bake another 20–25 minutes, or until the top is lightly golden and bubbling and the chicken pieces in the center reach at least 165°F (74°C) when checked with an instant-read thermometer.
If you’d like a deeper golden crust, you can place the casserole under the broiler for 2–3 minutes at the end, watching very closely so the Parmesan doesn’t burn.
Let the casserole rest on the counter for about 10 minutes before serving. This helps the layers settle and makes it easier to scoop out neat portions with a large spoon, revealing the creamy chicken and spinach underneath the browned Parmesan top.
Variations & Tips
You can easily adjust this old-fashioned casserole to suit your family and what you have on hand while still keeping the spirit of the five-ingredient original. If you don’t care for cream of mushroom soup, cream of chicken or cream of celery will work just as well and give a slightly different flavor, much like the way our mothers swapped soups depending on what was in the pantry. Fresh spinach can be used in place of frozen; just chop it and sauté briefly in a dry skillet until wilted and most of the moisture is gone before layering it in the dish. If you want a little more color and texture, stir a handful of shredded mozzarella or Swiss into the sauce, or mix a few buttered breadcrumbs with the Parmesan for a crunchier topping. Dark meat lovers can substitute boneless, skinless chicken thighs; they stay very moist and are more forgiving if left in the oven a few minutes longer. For a milder flavor, reduce the Parmesan and add a spoonful of cream cheese into the sauce for extra creaminess. Food safety tips: Always thaw frozen spinach in the refrigerator or in the microwave, never on the counter, and squeeze out excess liquid so the casserole bakes evenly. Keep raw chicken refrigerated until you’re ready to assemble, and wash your hands, cutting board, and knife thoroughly with hot, soapy water after handling it to avoid cross-contamination. Make sure the casserole reaches an internal temperature of at least 165°F (74°C) in the center before serving; using an instant-read thermometer takes out the guesswork. Leftovers should be cooled, then refrigerated within 2 hours and eaten within 3–4 days, reheated until steaming hot all the way through.
