Farfalle with Spinach, Mushrooms, and Caramelized Onions

Farfalle with Spinach, Mushrooms, and Caramelized Onions
Ingredients (Serves 4)
12 oz farfalle (bow-tie pasta)

2 tablespoons olive oil

1 tablespoon butter

2 large yellow onions, thinly sliced

10 oz cremini or white mushrooms, sliced

3 cups fresh baby spinach (or more to taste)

3 cloves garlic, minced

Salt and pepper, to taste

1/2 teaspoon dried thyme (optional)

1/4 cup grated Parmesan cheese (optional)

Red pepper flakes (optional, for heat)

Instructions