Sheet Pan Mushroom and Polenta Bake
A rustic Italian-inspired sheet pan bake combining creamy polenta with sautéed mushrooms and melted cheese for a comforting vegetarian meal. This italian-inspired sheet pan (vegetarian) ready in about 40 minutes pairs instant polenta, water, salt for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 280 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.
Ingredients
- 1 cup instant polenta
- 4 cups water
- 1 tsp salt
- 3 tbsp olive oil
- 12 oz cremini mushrooms, sliced
- 3 cloves garlic cloves, minced
- 1 tbsp fresh thyme leaves
- 1 cup mozzarella cheese, shredded
- 1/4 cup parmesan cheese, grated
- 1/2 tsp black pepper
Equipment for this recipe
Top-rated tools to make this recipe successfully.
Instructions
- Step 1: Preheat oven to 400°F. In a medium saucepan, bring 4 cups water and 1 tsp salt to a boil. Slowly whisk in 1 cup instant polenta and reduce heat to low. Cook, stirring frequently, for 5 minutes until thickened and creamy.
- Step 2: While polenta cooks, heat 2 tbsp olive oil in a skillet over medium-high heat. Add 12 oz sliced cremini mushrooms, 3 minced garlic cloves, and 1 tbsp fresh thyme leaves. Sauté for 6-8 minutes until mushrooms are browned and fragrant.
- Step 3: Pour the cooked polenta into a greased 9x13 inch sheet pan and spread evenly. Top with the sautéed mushrooms mixture. Sprinkle 1 cup shredded mozzarella and 1/4 cup grated parmesan evenly over the top. Drizzle 1 tbsp olive oil and 1/2 tsp black pepper over everything.
- Step 4: Bake uncovered for 15-20 minutes until cheese is melted, bubbly, and golden on the edges. Let cool 5 minutes before slicing and serving.
Frequently asked questions
How long does Sheet Pan Mushroom and Polenta Bake take to make?
Total time is about 40 minutes (10 min prep + 30 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.
How do I store leftover Sheet Pan Mushroom and Polenta Bake?
Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep instant polenta from drying out.
Can I substitute ingredients in Sheet Pan Mushroom and Polenta Bake?
Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.
How do I scale Sheet Pan Mushroom and Polenta Bake for a different number of people?
The recipe is written for 6 servings. Multiply each ingredient by (your serving target / 6). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.
Is Sheet Pan Mushroom and Polenta Bake vegetarian?
Yes — this recipe is tagged vegetarian based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.
