Garlic Butter Mushroom and Cheese Polenta Skillet for a Rich One-Pan Dinner Step-by-step instructions

Before you start

Gather every ingredient and tool before you turn on the stove, because the polenta needs steady stirring and the mushrooms need attention once the butter is hot. Set out the cremini and king oyster mushrooms on a cutting board and trim any tough stem ends. Slice the cremini into even pieces with a chef's knife, then slice the king oyster mushrooms the same way so they brown together.

Thinly slice the pink shallots and set them aside. Mince the garlic, pick the thyme leaves from their sprigs and keep a few whole sprigs for serving. Grate the aged hard cheese on a box grater and cut the Taleggio into small pieces after removing the rind. Snip the chives and place them within reach. Measure the water, milk and coarse polenta, and have a whisk and a wooden spoon ready.

Instructions

Mushrooms are golden

1. 1Prepare the mushrooms and shallots
   Trim the cremini and king oyster mushrooms, then slice them into even pieces with a chef's knife. Thinly slice the pink shallots and grate the aged hard cheese on the large holes of a box grater, so it is ready to top the polenta and the mushrooms.
   Look for Mushroom slices are even, and a fluffy pile of grated cheese sits on the board.
   Tip Slice the mushrooms in similar sizes so they brown at the same rate in the pan.
2. 2Cook the polenta
   Bring the water and milk to a simmer in a medium saucepan with a pinch of salt. Whisk in the coarse polenta slowly, then reduce the heat to low and stir often for about 25 minutes until thick and creamy, then stir in the Taleggio and half the grated hard cheese until melted.
   Look for The polenta is thick, glossy and pulls away from the sides of the pan.
   Tip Stir from the bottom of the pan so the polenta does not scorch or stick.

The polenta should be thick and creamy, with a smooth glossy surface that pulls gently away from the sides of the saucepan when you stir. The Taleggio and half of the grated hard cheese should have melted fully into it, leaving no stringy strands or grainy patches. Stir in a small pinch of salt and taste it, because the cheese adds salt of its own. If the polenta looks stiff, loosen it with a splash of warm milk, a spoonful at a time. Keep it warm over low heat while you cook the mushrooms, and stir occasionally so the bottom does not catch and scorch.

Polenta spread and topped

3. 3Brown the mushrooms in garlic butter
   Melt the butter in the cast iron skillet until it foams. Add the sliced mushrooms in a single layer and sauté, stirring occasionally, until golden brown and their moisture has evaporated. In the final moments, fold in the minced garlic and thyme leaves until fragrant, then season with salt and pepper.
   Look for The mushrooms are golden brown, dry to the touch and smell of garlic and thyme.
   Tip Give the mushrooms room in the pan and do not stir too often, so they color well.
4. 4Assemble the cheesy polenta base
   Spread the warm, creamy polenta evenly in the cast iron skillet. Top it with the remaining grated hard cheese so it melts into the warm polenta, and keep the skillet warm over low heat while you finish the mushrooms.
   Look for The cheese has melted into the polenta and the surface looks smooth and glossy.
   Tip Spread the polenta while it is still warm, because it sets quickly as it cools.

After the polenta is spread across the cast iron skillet, its surface should be smooth and even, with the remaining grated hard cheese melting into the warm top layer. The cheese should look softened and shiny, not dry or clumped, which shows the polenta is still warm enough to bind it.

Check the edges of the skillet, where the polenta cools fastest, and gently press them with the back of a spoon to keep an even layer. Before moving on, confirm that the skillet is still warm to the touch and that the mushrooms are ready to spoon over the top. Serve soon after assembly, while the base is still soft and warm.

Dish ready to plate

5. 5Plate the polenta and mushrooms
   Spoon the cheesy polenta into a shallow bowl for each serving. Arrange the browned garlic butter mushrooms over the top, then finish with more grated hard cheese, a few sprigs of fresh thyme and snipped chives. Serve right away while the polenta is warm.
   Look for The mushrooms sit glossy over the polenta and the cheese starts to soften on top.
   Safe temperature 145°F (63°C) internal temperature (shellfish)
   Tip Spoon some of the butter from the pan over the mushrooms for a richer finish.

Each serving should look rich and cohesive, with a generous spoonful of melted cheese polenta in a shallow bowl and the browned mushrooms piled neatly on top. The mushrooms should appear glossy from the butter and the garlic and thyme should smell fragrant rather than bitter. Finish with grated cheese, thyme sprigs and snipped chives so the colors stand out against the pale polenta. Check that the polenta is still warm and the cheese is partly melted on top before serving. If the bowls feel cool, warm them briefly under hot water before you fill them.

Common mistakes

The most common mistake is crowding the mushrooms into the pan. When the skillet is packed, the mushrooms release moisture that has nowhere to go and they steam instead of browning, leaving pale, rubbery pieces. Cook them in batches if needed, and let the moisture evaporate fully before adding the butter's flavor. Another frequent error is adding the garlic too early, which scorches it and makes the whole pan taste bitter.

Wait until the mushrooms are golden and nearly dry, then add the garlic and thyme for the final moments only. With the polenta, the usual problem is heat that is too high, which makes the bottom burn and the texture clump. Keep the flame low, stir often and add the cheese off the heat or at very low heat, so it melts smoothly without turning oily.

How to tell it’s done

The mushrooms are done when they are deep golden brown on the edges, dry to the touch and no longer releasing liquid into the pan. They should smell toasty and savory, with the garlic and thyme fragrant but not browned. The polenta is ready when it is thick, smooth and creamy, holds its shape in a spoon and feels glossy rather than grainy.

The cheese should be fully melted through the base. This dish contains no raw meat, poultry, fish or eggs, so there is no internal safe-temperature target. Instead, rely on color, texture and aroma: a pan of golden mushrooms and a smooth, glossy polenta base are the signs that it is ready to serve.

• Shellfish: 145°F (63°C) in the thickest part