How to Make It
Heat the 3 tablespoons of grapeseed oil in a large saucepan over medium heat. Add the onions, mushrooms, and rosemary; season with salt and pepper. Cook, stirring occasionally, until the vegetables are softened and browned, 15 to 20 minutes. Add the wine and cook over medium-high, scraping up any browned bits from the bottom of the pan, until reduce by half, about 2 minutes. Add the stock and simmer until the mushrooms and onions are coated in a light sauce, about 5 minutes. Season the mushroom sauce with salt and pepper.
Meanwhile, beat together the eggs, sour cream, mace, nutmeg, and a pinch each of salt and pepper in a shallow bowl. Mix together the panko and parmigiano in another shallow bowl. Mix the flour with a generous pinch each of salt and pepper in a third shallow bowl.
Season the pork with salt and pepper. Work with one piece of pork at a time: Dredge the pork in the flour, shaking off the excess. Dip the floured pork in the egg mixture, letting the excess drip back into the bowl, and then dredge it in the panko mixture; gently shake off any excess panko. Repeat with the remaining pork.
Heat ¼ inch of grapeseed oil in a large cast-iron skillet over medium-high. Add one piece of schnitzel to the skillet and cook, turning once, until browned and crisp, about 6 minutes total. Transfer to paper towels to drain; sprinkle with flaky sea salt and finely grated lemon zest. Repeat with the remaining schnitzel. Transfer the schnitzel to plates and top with the mushroom sauce. Serve with whole-grain mustard, passing additional sauce at the table.
Big green salad