How to Make It
Place the potatoes in a pot. Add cold water to cover; bring to a boil. Add 1 teaspoon salt, reduce heat, and simmer until tender, 15 to 18 minutes. Drain and return potatoes to the pot. Add the buttermilk, 4 tablespoons butter, 1 teaspoon salt, 1/8 teaspoon pepper, and nutmeg. Mash. Set aside, keeping warm.
Meanwhile, heat the oil in a skillet over medium-high heat. Season the pork with 1 ½ teaspoons salt, ¼ teaspoon pepper, and paprika. Cook until browned, 3 minutes per side.
Cover skillet, reduce heat to medium, and cook until cooked through, about 6 to 8 minutes.
Meanwhile, melt the remaining butter in another skillet over medium heat. Add onion the and garlic; cook until softened, 3 to 4 minutes.
Add the mushrooms and cook until they release their liquid and begin to brown, about 8 minutes. Add the wine, thyme, and zest; simmer until liquid has nearly evaporated, 3 to 4 minutes.
Add the broth, cream, ½ teaspoon salt, and ¼ teaspoon pepper. Bring to a boil. Reduce heat and simmer until sauce lightly coats the back of a spoon. Serve with the pork, mashed potatoes, lemon wedges, and romaine.