4 large pork loin cuts, about 1 inch thick
1 pound cremini mushrooms, washed and sliced
1 teaspoon poultry seasoning
Salt and freshly ground black pepper to taste
2 tablespoons olive oil
1 tablespoon butter
1 large yellow onion, sliced
4 cloves garlic, minced
1 1⁄2 tablespoons all-purpose flour
1 1⁄2 cups chicken broth
1⁄4 cup buttermilk
1⁄4 cup water
Sprinkle pork loin with poultry seasoning, salt, and black pepper on both sides. Heat olive oil in a large skillet over medium-high heat; brown pork loins well on both sides, about 5 minutes per side. Transfer to a plate.
Melt butter in the same skillet. Reduce heat to medium and stir onion and mushrooms in the hot skillet with a pinch of salt until both are very browned and caramelized, about 15 minutes. Stir in garlic and cook for 1 minute; stir in flour and cook for 2 minutes.
Pour chicken broth into the skillet and stir, dissolving browned bits of food in the bottom of the skillet. Pour juices that have accumulated on the plate containing pork loins into the sauce. Mix in buttermilk until smooth. Add water. Bring sauce to a simmer, reduce heat to low, and cook until onions begin to break down and sauce is thickened, 15 to 20 minutes.
Place pork loins into sauce, spooning sauce over meat to coat. Turn heat to low and simmer until lions are tender and cooked through, about 10 minutes. Adjust levels of salt and pepper and serve loins with gravy on top.