I started making this on nights when I had a tube of polenta in the fridge and not much else. It sounds like it shouldn’t work — roasted mushrooms, polenta rounds, all on one little tray — but it absolutely does, and it comes together in under 35 minutes without dirtying more than one bowl.
The miso butter is the thing that makes it. White miso and butter already want to be together; they’re salty and rich and faintly sweet, and they give the mushrooms this deep, almost meaty glaze that tastes like it took way more effort than it did. The honey is subtle — you’re not going for sweet, just a little rounding out of the edges. One clove of garlic or two? Personally I go two.
For this you’ll want a toaster oven that actually fits a standard sheet pan, or at least a 9×11 tray — something like a large-capacity toaster oven makes the whole thing easier since you’re fitting polenta rounds and mushrooms side by side. A toaster oven baking sheet with a lip is also worth having so the mushroom juices don’t drip down to the heating element.
This is vegetarian and honestly filling enough that nobody’s complained. Serve it as a main with a simple green salad, or as a side if you want. It’s a bit of a chameleon that way.
Toaster Oven Miso Butter Roasted Mushrooms on Crispy Polenta
Savory roasted mushrooms glazed with white miso and butter, served over golden pan-crisped polenta rounds. Ready in about 30 minutes and wildly satisfying for a weeknight.
Ingredients
Polenta Rounds
Miso Butter Mushrooms
To Finish
Instructions
Prep and Start the Polenta
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Preheat your toaster oven to 425°F. Line the toaster oven tray with foil and give it a light brush of olive oil so nothing sticks.
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Slice the polenta tube into rounds roughly ½ inch thick — you should get about 12. Brush both sides with olive oil, then sprinkle with garlic powder and salt.
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Lay them flat on one half of the tray and slide it in. Roast for 10 minutes.
Make the Miso Butter and Prep Mushrooms
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While the polenta starts cooking, whisk together the melted butter, miso paste, soy sauce, honey, and minced garlic in a medium bowl. It'll look a little thick. That's fine.
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Toss the halved mushrooms into the bowl and stir until they're coated all over.
Roast Everything Together
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After the polenta's had 10 minutes, flip each round. Tip the mushrooms onto the other half of the tray in a single layer — or as close to one as you can manage.
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Roast everything together for another 12 minutes. The mushrooms should look deeply browned and a little caramelized at the edges. The polenta should be golden and just slightly crisp on the bottom.
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If your mushrooms aren't as brown as you'd like, switch to broil for 2 minutes and keep an eye on them.
Assemble and Serve
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Arrange the polenta rounds on a plate or shallow bowl. Pile the mushrooms on top, then squeeze a little lemon over everything.
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Scatter the chives and sesame seeds over the top and serve right away. These don't really hold — eat them while the polenta is still crispy.
Notes
White miso is the one to use here. Red or brown miso is stronger and can turn a little bitter when it roasts. If your toaster oven runs hot (mine does), check the mushrooms at the 9-minute mark — they can go from perfect to too dark fast. Tube polenta varies a lot by brand; Trader Joe's and San Gennaro both work well. You can absolutely make this with shiitake or a mixed mushroom blend instead of creminis. Just pull out any tough stems first.
Nutrition
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Written by
Emma is a home cook who loves coaxing big flavor out of a toaster oven — from crispy roasted vegetables to easy weeknight dinners and sweet treats. She develops and tests Toastera's recipes for small-appliance kitchens.
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