Brown ground beef in a large skillet over medium-high heat, stirring and breaking meat up. Transfer ground beef to a bowl.

Melt butter in the same skillet; add zucchini and sauté until slightly softened, about 5 minutes.

Return ground beef to the skillet. Add water, tomatoes, Knorr rice, dried onion, and Worcestershire sauce. Bring to a boil over high heat. Reduce heat to low; cover and cook, about 7 minutes.

Season with salt and pepper, and top with cheese. Let sit 5 minutes before serving.