In a large, deep skillet, heat the olive oil over medium heat. Once it's hot, add the mushrooms with a pinch of salt and pepper and cook them, stirring occasionally, until they are browned and softened. Then add the garlic and cook until just fragrant.
Stir in the beans, tomato sauce and seasonings to the pan and let it come up to a simmer. Once simmering, let it cook for 10 or so minutes. Then stir in the spinach. Once the spinach wilts down, add the cheese over the top and pop a lid on to let it melt. Or if your skillet is oven-safe, you can pop it under the broiler for a couple minutes. Then serve it up.
Pictured here as leftovers served over red lentil pasta. I added some heavy cream and zucchini to the leftovers and heated it all through on the stovetop.
