Thaw the frozen spinach at room temperature or in the refrigerator until completely thawed, then drain in a colander and press out all excess liquid.

Preheat your oven to 350°F (175°C).

Soften the cream cheese by letting it sit at room temperature for 5 to 10 minutes.

Peel and mince the garlic cloves finely.

In a large mixing bowl, combine the softened cream cheese, sour cream, mayonnaise, salt, and black pepper, stirring until smooth.

Stir in the shredded mozzarella and parmesan cheese until evenly distributed.

Fold in the drained spinach until fully combined.

Spoon the mixture into the baking dish, spreading it evenly, and sprinkle the panko breadcrumbs on top if using.

Bake for 18 to 22 minutes at 350°F (175°C), until the dip is bubbly around the edges and light golden on top.

Let the dip rest for 2 to 3 minutes before serving so it sets slightly.