Unwrap the polenta and slice it into 1/2-inch slices. Line a plate with paper towels.
Melt 1 tablespoon of the butter in a large skillet over medium-high heat. Place as many of the polenta disks into the pan as will fit in a single layer. Cook without moving them, until they turn golden brown and start to crisp up on the bottom, about 5 minutes. Flip the slices with a spatula, and continue to cook until the second side is browned and slightly crispy, about another 5 minutes.
Remove the polenta to the paper towel-lined plate. Repeat with another tablespoon of butter and the remaining polenta slices. Add those to the first batch.
Meanwhile, in another skillet, melt the remaining tablespoon of butter, then add the mushrooms and garlic, and season with salt and pepper. Sauté for 8 to 10 minutes until the liquid has evaporated and the mushrooms have turned nicely browned.
Spoon the hot sauteed mushrooms over the polenta slices, sprinkle over the parsley and serve warm.
Notes
Whenever I sauté mushrooms, I try to make more than I need for that meal or recipe since leftover sautéed mushrooms are so amazing to have on hand. You can add them to omelets, sauces, or soups and use them to top anything from a burger or a steak to these vegetarian bites. Make sure to allow the mushrooms to sauté long enough that they release all of their liquid and start to caramelize.If you make your own polenta or use packaged premade polenta, you can check to see if it’s vegan. If you are looking to keep this dish vegan, just use olive oil instead of butter.