Place a large skillet over medium-high heat. Melt the butter and add the garlic, cook and stir for 1-2 minutes (don't let garlic burn). Add in the zucchini noodles and spinach. Gently toss and cook until spinach leaves are wilted, about 2-4 minutes. Stir in 1/4 cup of the Parmesan cheese and toss until zucchini noodles are coated in the parmesan cheese. Season with salt and freshly ground black pepper, to taste.