Spinach and Ground Beef Casserole

Ingredients

• 2 boxes frozen chopped spinach, thawed and squeezed dry
• 1 cup finely chopped onion
• 2 cups shredded mozzarella cheese, divided
• ¾ cup French-fried onions
• 1 lb. ground beef
• 4 ounces cream cheese, softened
• ½ cup sour cream, at room temperature
• ½ teaspoon kosher salt
• ½ cup milk, at room temperature
• 1 can condensed cream of mushroom soup, NOT diluted
• 1 tablespoon minced fresh garlic