4cupssliced mushrooms such as oyster, maitake, cremini or shiitake
12ouncesbeef sirloin, thinly sliced ask your butcher to slice it for you
1cup beef broth
2cups packed baby spinach leaves stems trimmed
sour creamfor serving
chopped fresh parsleyfor garnish
grated lemon zestfor garnish
For the Polenta
In a medium saucepan, heat 4 1/2 cups water over medium heat. Add the salt and bring to a boil. Whisk in the polenta and reduce the heat to medium-low. Cook, stirring frequently to eliminate lumps and prevent burning, until the polenta is thickened and cooked through, about 15 minutes.
For the Stroganoff:
In a large skillet, heat 2 tablespoons of the olive oil over medium heat. Add the onions and shallot and cook, stirring, until soft, 6 to 8 minutes. Add the garlic and thyme and cook, stirring, until fragrant, about 1 minute. Season with salt and pepper. Add the mushrooms and cook, stirring, until the liquid released by the mushrooms has evaporated and the mushrooms brown, 8 to 10 minutes. Remove the thyme sprigs from the mixture and discard. Transfer the mixture to a large bowl. Set aside.
In the same skillet, heat the remaining 2 tablespoons olive oil over medium-high heat. Add the brandy, return the skillet to the heat, and use your spoon to scrape up all the bits on the bottom of the pan. Let the brandy simmer for 2 minutes. Add the broth and let it come to a simmer. Stir in the spinach and let them wilt before returning the mushrooms and meat to the pan. Cook just long enough to heat through. Adjust the seasoning with the salt and pepper, if desired.
Top the polenta with the stroganoff and serve with sour cream, parsley, and lemon zest.