Preheat your oven to 350°F (175°C) and spray a 7½"x10" baking dish with nonstick cooking spray.

Cook broccoli florets in the microwave as per package instructions or chop fresh into bite-sized pieces and microwave with water for 4-5 minutes until tender.

In a large mixing bowl, combine steamed broccoli, softened cream cheese, mayonnaise, crushed garlic, onion powder, salt, black pepper, shredded cheddar cheese, and fresh spinach. Mix until creamy.

Spread the mixture evenly into the prepared baking dish, smoothing the top.

Sprinkle shredded mozzarella cheese on top, ensuring even coverage.

Bake in the preheated oven for 30-35 minutes until golden brown and bubbly.

Let cool for 5-10 minutes before serving.