- 1/4 cup good quality extra virgin olive oil
- 1 large sweet onion, sliced vertically into thick slices, about 2 cups
- 1 tablespoon fresh garlic, chopped
- 8 ounces sliced mushrooms, about 2 cups
- 1 15–ounce can white cannellini beans drained
- 1 14.5–ounce can stewed tomatoes (or use our homemade recipe). Remove tomatoes, roughly chop and add back to juice
- 1/4 teaspoon dry red pepper flakes
- 1 teaspoon dry oregano
- 1/2 teaspoon kosher salt
- 1/4 teaspoon freshly ground black pepper
- 1 pound fresh baby spinach
- Juice from half a lemon
- 4 ounces crumbled feta cheese, divided