Caramelized Onion Sauce with Sautéed Spinach and Mushrooms
A rich and savory sauce featuring golden caramelized onions, tender spinach, and earthy mushrooms—perfect over pasta, chicken, or toast.
- Prep Time: 10 minutes
- Cook Time: 35 minutes
- Total Time: 45 minutes
- Yield: 4 servings
- Category: Sauce, Side Dish, Topping
- Method: Stovetop, Sautéing
- Cuisine: American, Vegetarian
- Diet: Vegetarian
Ingredients
2 tbsp olive oil or butter
2 large yellow onions, thinly sliced
1/2 tsp salt
1 tsp sugar (optional, to help caramelize)
8 oz mushrooms (cremini or button), sliced
2 cloves garlic, minced
4 cups baby spinach
1/4 tsp black pepper
1/4 tsp thyme (optional)
1/4 cup vegetable or chicken broth (for deglazing)
1–2 tbsp heavy cream or plant-based alternative (optional for creaminess)
Grated Parmesan (optional for serving)
Instructions
Caramelize Onions: In a large skillet, heat olive oil over medium-low heat. Add sliced onions, salt, and sugar (if using). Cook, stirring occasionally, for 25–30 minutes until deep golden brown.
Add Mushrooms & Garlic: Stir in mushrooms and cook until softened and browned, about 6–8 minutes. Add garlic and thyme; cook 1 minute.
Add Spinach: Toss in spinach and cook until just wilted.
Deglaze & Finish: Add broth to deglaze the pan, scraping up browned bits. Stir in cream (if using) and adjust seasoning with salt and pepper.
Serve: Use as a sauce for pasta, rice, grilled meats, or toast.
Notes
Make it vegan by using plant-based butter and cream.
Add a splash of balsamic vinegar for a tangy finish.
Great as a topping for baked potatoes, burgers, or risotto.
Can be made ahead and refrigerated for up to 3 days.
