Melt the butter in a medium skillet over medium heat.
Add the onion and sauté until soft and translucent, stirring frequently.
Add the garlic and stir for 1 minute, being careful not to burn the garlic. Add green and yellow zucchini, and parsley.
Cook until zucchini is soft and just becoming translucent, about 4 - 5 minutes. Remove from heat, season with salt and pepper, sprinkle with crumbled bacon and serve immediately.