Stuffed Portabella Mushrooms with Polenta
By Emma
Certified Culinary Professional
•
Recipe tested & approved
Polenta cooked in vegetable broth, infused with butter for creaminess. Bell peppers, cucumber swapped for zucchini for freshness; combined with red onion, garlic, oregano, bread crumbs, egg binding, black pepper and salt. Mozzarella shredded throughout and on top, melts into golden bubbly pockets. Portabellas wiped clean, oiled for roasting. Stuffed, baked till juices glisten and edges brown. Marinara warmed to rich aroma, poured over for acidic punch. Parsley brightens; Maldon salt for crunch. Timing varies by mushroom size; feel for softness. Substitutions include cornmeal for polenta, goat cheese for mozzarella, and vegan egg replacer. Quick, forgiving, rustic in texture and smell.
Prep:
12 min
Cook:
17 min
Total:
29 min
Servings:
4 servings
#mushroom recipes
#Italian-inspired
#vegetarian
#baked dishes
#easy weeknight
Forget fussing over delicate fillings. That mushroom gill texture, when roasted just right, a little chewy, a little yielding, pairs beautifully with polenta’s comforting grit and buttery silk. Zucchini swaps crisp cucumber for better roasting texture without soggy aftermath. Toasty bread crumbs and an egg hold the stuffing together—essential or you’ll see a sloppy flop. Mozzarella melts in pockets and browns under heat, giving that satisfying chew and stretch. Warm marinara cuts through the earthiness, wakes up the palate. Parsley and flaky sea salt finish like a wink. Learn to trust feel here, not numbers; mushrooms are moody, interactions vary. That’s where practice shines. No exact precision. Just senses on alert.
Ingredients
- 4 large portabella mushroom caps
- 4 cups vegetable or chicken stock
- 1 cup dry polenta or fine cornmeal
- 1/2 teaspoon fine sea salt plus more to taste
- 1 medium red bell pepper, diced
- 1 medium zucchini, diced (instead of cucumber)
- 1/4 cup red onion, finely chopped
- 2 cloves garlic, minced
- 1 teaspoon dried oregano
- 1/3 cup bread crumbs
- 1 large egg
- 1/2 teaspoon freshly ground black pepper
- 3/4 cup shredded mozzarella cheese, divided
- 2 tablespoons unsalted butter
- 1 cup marinara sauce, warmed
- Extra virgin olive oil for brushing
- Chopped fresh parsley for garnish
- Maldon sea salt flakes for finishing
About the ingredients
Vegetable stock is preferable if you want lighter body; chicken stock adds richness. Polenta can be replaced with fine cornmeal but expect texture to vary slightly—cornmeal flowers tend to be grainier. Swapped cucumber with zucchini because it holds shape better when baked and doesn’t release excess water, keeping the stuffing from becoming mushy. Mozzarella you can swap for goat cheese or fontina for tangier or creamier notes. If avoiding eggs, use a flaxseed egg (1 tbsp flax + 3 tbsp water, set 5 mins) for binding but expect subtler hold. Olive oil must be good quality; cheap oils burn and dull flavor. Bread crumbs should be fresh for crisp texture; stale crumbs soak moisture and kill crunch.
Method
- Warm stock in saucepan; once bubbling, whisk in polenta and 1/2 tsp salt. Cover, reduce heat low; cook stirring every few minutes to avoid lumps. Polenta should thicken but remain creamy; add water in small bits if too stiff.
- Roughly chop bell pepper and zucchini into similar sizes so stuffing cooks evenly. Toss with chopped onion, garlic, oregano, breadcrumbs, egg, pepper, salt, and 1/2 cup shredded mozzarella. Mix until combined but not overly wet.
- Clean mushroom caps gently with damp cloth; scrape out stems if woody. Lay them gill side up on parchment-lined baking sheet. Brush surfaces with olive oil until glistening; this prevents drying and adds flavor.
- Divide stuffing into each cap, pressing lightly to pack but keep loose texture. Don’t overfill - mushrooms shrink and release moisture as they roast.
- Bake at 355 degrees Fahrenheit, give or take 5 degrees for your oven quirks, for 17 minutes or until mushrooms soften to tender but not mushy. Tops should be golden, edges crisping slightly, juices pooling around edges.
- Meanwhile, warm marinara sauce in small pot until aromatic and simmering gently.
- Remove polenta from heat; fold in butter for richness and shine. Adjust consistency with hot water if polenta feels too dry. Should spoon easily but hold shape; think soft yet sturdy pudding.
- Plate by scooping polenta in center, overlay a stuffed mushroom. Spoon warmed marinara over mushroom and sprinkle remaining mozzarella on top, letting residual heat melt it slightly.
- Finish with chopped parsley scattered for color and Maldon salt flakes for bursts of crunch and seasoning.
- If mushrooms seem watery keep baking a few minutes. Mushrooms vary wildly by size and moisture; trust your eyes and touch more than the clock.
Cooking tips
Start polenta early; it needs stirring to avoid lumps but not constant attention. Polenta thickens as it cools, so keep heat low and stir intermittently until creamy and yielding. Mushroom caps cleaned well—never rinse under water blindly, they soak up moisture. Brush oil well, especially on gill side to prevent sticking and drying. Stuffing mix can feel wet but resist adding more crumbs; the egg and cheese will firm up during baking. Bake time varies; mushrooms should wrinkle, gills darken but not dry like jerky. Check firmness by pressing center gently with fingertip—it should yield but bounce slightly. Polenta consistency is key; if dry, add reserved hot water bit by bit—it should spoon off smoothly like thick pudding. Apply marinara after baking to preserve vibrant tomato flavor; cheese sprinkled last melts from residual heat, creating gooey goodness without drying out.
Chef's notes
- 💡 Polenta thickens fast once off heat, don’t let it dry out or becomes crumbly. Stir frequently when cooking, low heat only. If too stiff, add hot water in spoonfuls, keeps creamy but firm. Butter folded last makes it silky yet stable.
- 💡 Clean mushrooms carefully; don’t soak, water ruins roasting texture. Use damp cloth or paper towel, scrape stems out if tough or dry. Oil gill side heavily, helps prevent sticking and promotes crisp edges.
- 💡 Stuffing needs balance of moist veggies and dry crumbs to hold shape without going soggy. Egg binding crucial. Too wet stuffing causes soggy mushrooms. Mozzarella should be divided. Keep part inside mix, part sprinkled on top to melt and brown.
- 💡 Roast at 355°F allow for 16-18 minutes, but check texture by feel. Mushrooms soften but shouldn’t collapse. Gills darken slightly, edges turn crisp but not burnt. Juices bubble around edges signal near done. Adjust time per mushroom size.
- 💡 Marinara warms separately, spoon after baking to keep freshness. Cheese on top melts from residual heat, adds gooey layer without drying out topping. Parsley chopped just before serving for bright notes. Maldon flakes for crunchy bursts; add last.
Common questions
Can I swap polenta with cornmeal?
Yes but texture shifts. Cornmeal grainier, less creamy. Use fine cornmeal, cook gently. Adjust water amounts carefully. Expect slightly grainier mouthfeel, not bad just different.
What if mushrooms release too much water?
Blot mid-roast if soggy. Longer roast time helps moisture evaporate. Avoid washing mushrooms under water. Oil well to protect texture. Stuff tight but not packed, mushy stuffing worsens.
How to make vegan version?
Replace egg with flaxseed mix, 1 tbsp flax to 3 tbsp water, sit 5 mins. Swap mozzarella with plant-based cheese or omit but lose melt/stretch. Use vegetable stock. Butter replaced with vegan margarine or olive oil.
Best way to store leftovers?
Cool fully, seal airtight container. Fridge up to 3 days. Reheat gently in microwave with splash of water or oven at low heat to restore softness. Polenta thickens after chilling; add water if needed when reheating.
