Gather and prepare all ingredients.
Heat a large skillet over medium-high heat.
Add the ground beef and diced onion. Cook for 5–7 minutes, stirring frequently, until the beef is browned and the onion becomes soft and translucent.
Drain any excess grease from the skillet.
Crush the stewed tomatoes into smaller pieces and add them to the skillet.
Stir in the mushrooms, tomato sauce, black olives, minced garlic, salt, and white pepper.
Simmer uncovered for 20–30 minutes, allowing the mixture to reduce and develop flavor.
Slice the zucchini lengthwise, then cut into ½-inch half-moons.
Add the zucchini to the beef mixture and stir well.
Cover and cook for 5–7 minutes until the zucchini is tender but still slightly firm.
Sprinkle the shredded cheddar cheese evenly over the skillet.
Cover again and cook for 3–4 minutes until the cheese is completely melted.
Serve hot and enjoy your delicious Zucchini and Ground Beef Skillet.