Spicy Italian Sausage and Mushroom Polenta Bake

Quick Recipe Version (TL;DR)

• Yield: 6 servings
• Prep Time: 20 minutes
• Cook Time: 45 minutes
• Total Time: 1 hour 5 minutes

Quick Ingredients

• 1 lb (450 g) spicy Italian sausage, casings removed
• 8 oz (225 g) cremini or button mushrooms, sliced
• 1 small yellow onion, finely chopped
• 3 cloves garlic, minced
• 2 cups (480 ml) marinara sauce
• 2 tbsp tomato paste
• 1/2–1 tsp crushed red pepper flakes (to taste)
• 1 cup (160 g) polenta or coarse yellow cornmeal
• 4 cups (960 ml) low-sodium chicken broth
• 1 cup (240 ml) whole milk
• 2 tbsp unsalted butter
• 1 1/4 cups grated Parmesan cheese, divided
• 1 cup (100 g) shredded low-moisture mozzarella
• 2 tbsp olive oil
• Salt and freshly ground black pepper
• Fresh basil or parsley, chopped, for garnish (optional)

Do This

• 1. Preheat oven to 400°F (200°C). Grease a 2–3 quart baking dish.
• 2. Simmer marinara, tomato paste, and red pepper flakes together for 5–10 minutes; set aside.
• 3. Brown sausage in olive oil, breaking it up. Add onion, mushrooms, and garlic; cook until tender and browned.
• 4. Bring broth and milk to a simmer; slowly whisk in polenta. Cook, stirring often, 15–20 minutes until thick and creamy. Stir in butter, 1 cup Parmesan, salt, and pepper.
• 5. Spread polenta in baking dish. Top with sausage-mushroom mixture, then spoon over the chili-spiked marinara. Sprinkle with mozzarella and remaining Parmesan.
• 6. Bake 20–25 minutes until bubbling and golden. Rest 5–10 minutes, garnish with herbs, and serve hot.

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Why You’ll Love This Recipe

• Comforting layers of creamy polenta, spicy sausage, and rich marinara baked into one rustic, cozy dish.
• Perfect make-ahead meal for busy nights, potlucks, or relaxed weekend dinners.
• Simple pantry-friendly ingredients with big Italian flavors and just the right level of heat.
• Easily adaptable: dial the spice up or down, swap sausages, or make it more veggie-forward.

Grocery List

• Produce: 1 small yellow onion, 3 cloves garlic, 8 oz cremini or button mushrooms, fresh basil or parsley (optional).
• Dairy: Whole milk, unsalted butter, Parmesan cheese, low-moisture mozzarella cheese.
• Pantry: Polenta or coarse yellow cornmeal, chicken broth (low-sodium), marinara sauce, tomato paste, olive oil, crushed red pepper flakes, salt, black pepper.
• Meat: Spicy Italian sausage (about 1 lb / 450 g).

Full Ingredients

For the Chili-Spiked Marinara

• 2 cups (480 ml) marinara sauce (store-bought or homemade)
• 2 tbsp tomato paste
• 1/2–1 tsp crushed red pepper flakes, to taste
• 1/2 tsp dried oregano (optional)
• Salt and freshly ground black pepper, to taste

For the Sausage & Mushroom Layer

• 1 lb (450 g) spicy Italian sausage, casings removed
• 2 tbsp olive oil (divided, if needed)
• 1 small yellow onion, finely chopped
• 8 oz (225 g) cremini or button mushrooms, sliced
• 3 cloves garlic, minced
• 1/4 tsp salt (or to taste, depending on sausage)
• Freshly ground black pepper, to taste

For the Creamy Polenta Base

• 4 cups (960 ml) low-sodium chicken broth (or vegetable broth)
• 1 cup (240 ml) whole milk
• 1 cup (160 g) polenta or coarse yellow cornmeal
• 2 tbsp unsalted butter
• 1 cup (90 g) freshly grated Parmesan cheese
• 1 tsp kosher salt (or 3/4 tsp fine sea salt, to taste)
• 1/2 tsp freshly ground black pepper

For Topping & Finishing

• 1 cup (100 g) shredded low-moisture mozzarella cheese
• 1/4 cup (22 g) freshly grated Parmesan cheese
• Fresh basil or flat-leaf parsley, chopped (for garnish, optional)
• Extra crushed red pepper flakes, for serving (optional)

Step-by-Step Instructions

Step 1: Preheat the Oven and Prep the Dish

Preheat your oven to 400°F (200°C) with a rack in the center. Lightly grease a 2–3 quart (about 9×13-inch or similar) baking dish with a little olive oil or butter to prevent sticking.

Gather and measure all ingredients. Chop the onion, slice the mushrooms, mince the garlic, grate the cheeses, and remove the casings from the sausage if needed. Having everything ready will make the cooking process smoother and more enjoyable.

Step 2: Make the Chili-Spiked Marinara

In a small saucepan over medium heat, combine the marinara sauce, tomato paste, crushed red pepper flakes, and dried oregano (if using). Stir well to blend. Bring to a gentle simmer, then reduce the heat to low.

Let the sauce cook for 5–10 minutes, stirring occasionally, to thicken slightly and allow the flavors to deepen. Taste and season with a pinch of salt and black pepper if needed. Turn off the heat and set aside while you prepare the sausage and mushrooms.

Step 3: Brown the Sausage

Heat 1–2 tbsp olive oil in a large skillet over medium-high heat. Add the spicy Italian sausage, breaking it up with a wooden spoon or spatula into small crumbles as it cooks.

Cook for 6–8 minutes, stirring occasionally, until the sausage is well browned and cooked through. If there is a lot of excess fat in the pan, spoon off some, leaving about 1–2 tablespoons for flavor. Leave the sausage in the pan; you will build the mushroom mixture right on top.

Step 4: Sauté the Mushrooms and Aromatics

To the skillet with the sausage, add the chopped onion and sliced mushrooms. If the pan seems dry, drizzle in a little more olive oil. Cook over medium heat for 6–8 minutes, stirring occasionally, until the onion is soft and the mushrooms have released their moisture and turned golden in spots.

Add the minced garlic, 1/4 teaspoon salt (or to taste), and a few grinds of black pepper. Cook for 1–2 more minutes until the garlic is fragrant, being careful not to burn it. Turn off the heat and set the sausage-mushroom mixture aside while you make the polenta.

Step 5: Cook the Creamy Polenta

In a medium saucepan, bring the chicken broth and whole milk to a gentle simmer over medium heat. Once you see small bubbles around the edges, slowly pour in the polenta in a thin stream while whisking constantly to prevent lumps.

Reduce the heat to low. Continue to cook, whisking frequently (switch to a sturdy spoon as it thickens if you like), for 15–20 minutes, or until the polenta is thick, creamy, and pulls slightly away from the sides of the pan. If it becomes too thick or stiff before it is tender, whisk in a splash of hot water or extra broth.

Remove the pan from the heat. Stir in the butter, 1 cup grated Parmesan, 1 teaspoon kosher salt, and 1/2 teaspoon black pepper until smooth and glossy. Taste and adjust seasoning if needed; it should be well-seasoned and richly flavored.

Step 6: Layer the Bake

Immediately pour the hot polenta into your prepared baking dish, spreading it into an even layer with a spatula. It will start to set as it cools, so work fairly quickly.

Spoon the sausage and mushroom mixture evenly over the surface of the polenta. Next, pour or ladle the warm chili-spiked marinara over the sausage layer, spreading gently so it covers from edge to edge.

Sprinkle the shredded mozzarella evenly over the top, followed by the remaining 1/4 cup grated Parmesan. This combination will melt into a bubbly, golden-brown topping in the oven.

Step 7: Bake, Rest, and Serve

Place the dish in the preheated 400°F (200°C) oven and bake for 20–25 minutes, or until the sauce is vigorously bubbling around the edges and the cheese on top is melted, lightly browned, and starting to crisp in spots.

Remove the dish from the oven and let it rest for 5–10 minutes. This short rest helps the layers settle and makes it easier to scoop neat portions.

Sprinkle with chopped fresh basil or parsley, and, if you enjoy extra heat, a pinch more crushed red pepper flakes. Serve generous spoonfuls hot, directly from the baking dish.

Pro Tips

• Use coarse polenta if possible: Coarser grind polenta gives the best rustic, creamy-yet-textured base. If using fine cornmeal, start checking for doneness earlier and reduce cooking time slightly.
• Control the heat level: For milder spice, choose sweet Italian sausage and use only 1/4–1/2 teaspoon red pepper flakes. For extra kick, keep the spicy sausage and go up to 1 teaspoon flakes.
• Prevent lumpy polenta: Whisk constantly as you slowly pour the polenta into the hot liquid. If you get a few lumps, keep whisking vigorously; many will smooth out as it cooks.
• Brown for flavor: Let the sausage and mushrooms get nicely browned; those caramelized bits add big depth and a satisfying, meaty flavor.
• Rest before serving: A short rest after baking makes the polenta slice more cleanly while still staying creamy inside.

Variations

• Extra-vegetable version: Add 1 small diced red bell pepper and a handful of baby spinach to the mushroom mixture. Sauté the pepper with the onion, then wilt in the spinach at the end.
• Cheesy three-cheese twist: Swap half the mozzarella for smoked provolone or fontina, and add a few dollops of ricotta on top before baking for extra richness.
• Mild, kid-friendly bake: Use sweet Italian sausage, omit the crushed red pepper flakes, and add 1 tsp dried Italian seasoning to the marinara instead.

Storage & Make-Ahead

Let leftovers cool to room temperature, then cover the baking dish tightly or transfer portions to airtight containers. Refrigerate for up to 4 days. Reheat individual servings in the microwave until hot, or warm larger portions in a 350°F (175°C) oven, covered with foil, for 15–20 minutes. For make-ahead prep, you can assemble the entire dish up to the point of baking, cover tightly, and refrigerate for up to 24 hours. When ready to cook, let it sit at room temperature for about 20 minutes while the oven preheats, then bake, adding 5–10 extra minutes if needed until fully heated through and bubbly.

Nutrition (per serving)

Approximate values for 1 of 6 servings: about 700 calories; 32 g protein; 44 g carbohydrates; 40 g fat; 18 g saturated fat; 3 g fiber; 1,350 mg sodium (will vary based on sausage, broth, and cheeses used). For a lighter version, use turkey sausage, part-skim cheeses, and low-fat milk.