Add olive oil and ½ tablespoon butter to a large skillet and set over medium-high heat.

Add zucchini slices to the hot oil; season with salt and pepper and cook for 3 to 4 minutes, or until fork-tender. Remove zucchini from skillet and set aside. If there's any liquid in the skillet, wipe it out.

Return skillet to the burner and add remaining butter; melt butter over medium-high heat.

Stir in the onions and cook for 2 minutes, or until just softened.

Add mushrooms and cook for 5 to 7 minutes, or until tender and nicely browned. Stir occasionally.

Stir in garlic and herbs; cook for 20 seconds.

Return zucchini to the skillet and mix with the mushrooms; cook for 1 minute, or until heated through.

Pour in the vegetable broth and cook for 2 minutes.

Taste for salt and pepper and adjust as needed.

Remove skillet from heat.

Sprinkle with parsley and parmesan; serve.