Cook the Zucchini: Heat the olive oil and ½ tablespoon of butter in a large skillet over medium-high heat. Add the zucchini slices, season with salt and pepper, and cook for 3 to 4 minutes until tender. Remove the zucchini from the skillet and set aside. If there is excess liquid in the skillet, wipe it out.
Sauté Onions and Mushrooms: In the same skillet, add the remaining butter and let it melt over medium-high heat. Add the diced onion and cook for about 2 minutes, until softened. Stir in the mushrooms and cook for 5 to 7 minutes, until tender and browned, stirring occasionally.
Add Garlic and Herbs: Add the minced garlic and chopped herbs to the skillet and cook for about 20 seconds until fragrant.
Combine Ingredients: Return the zucchini to the skillet and mix with the mushrooms. Cook for 1 minute until everything is heated through. Pour in the vegetable broth and let it simmer for 2 minutes.
Season and Serve: Taste and adjust seasoning with salt and pepper if needed. Remove from heat and sprinkle with chopped parsley and grated Parmesan cheese. Serve immediately.
