Creamy Cheesy Spinach Dip

1 tablespoon olive oil, divided

1 small onion, finely chopped

2 cloves garlic, minced

2 (10 ounce) packages frozen spinach - thawed, drained, and chopped

½ cup milk

6 ounces cream cheese

½ cup shredded mozzarella cheese

¼ cup shredded Cheddar cheese

2 dashes Worcestershire sauce

salt and ground black pepper to taste

½ cup shredded mozzarella cheese

Preheat oven to 425 degrees F (220 degrees C). Grease a 1 1/2-quart shallow baking dish with 1 teaspoon olive oil.

Heat 2 teaspoons olive oil in a large pot over medium heat. Cook and stir onion and garlic in hot oil until lightly browned, 4 to 7 minutes. Add spinach and simmer until spinach is hot, about 5 minutes. Drain any liquid from the mixture and transfer to a bowl.

Pour milk into pot and return pot to medium heat. Melt cream cheese into the milk; cook and stir together about 3 minutes. Return spinach mixture to pot with 1/2 cup mozzarella cheese and Cheddar cheese; stir to combine. Season the mixture with Worcestershire sauce, salt, and pepper. Pour the mixture into the prepared baking dish and top with 1/2 cup mozzarella cheese.

Bake in preheated oven until bubbly and golden brown on top, 20 to 25 minutes.