Heat a large skillet over medium-high heat. Pour in olive oil and add butter. Once melted and shimmering, proceed to the next step.

Add sliced zucchini to the hot skillet, season lightly with salt and pepper, and cook for 3-4 minutes until tender and slightly golden. Remove and set aside.

In the same skillet, melt another 1/2 tablespoon of butter over medium heat. Add diced onion and sauté for about 2 minutes until softened.

Add sliced mushrooms to the skillet and cook for 5-7 minutes, until browned and moisture is released.

Once the mushrooms are browned, add minced garlic and any fresh herbs. Stir and cook for about 20 seconds.

Return sautéed zucchini back to the skillet, pour in vegetable broth, and toss. Let simmer for 2 minutes.

Taste and adjust seasoning with salt and pepper. Remove from heat and sprinkle chopped parsley and grated Parmesan cheese.

Serve warm as a side dish or enjoy on its own.