Melt butter over medium high heat in a non-stick pan.
Add onion and garlic and sauté until the onion has softened, about 5-6 minutes.
Add spinach and toss well with garlic butter mixture. Sauté until just wilted, stirring frequently about 2-3 minutes. Season with salt and pepper to taste and give everything a big stir to evenly distribute seasonings.
Serve and enjoy!