In a medium saucepan, combine the minced garlic, the well-drained spinach, softened cream cheese, sour cream (or Greek yogurt), grated Parmesan cheese, and dried minced onion.
Cook this mixture over medium heat, stirring frequently, for about 5 to 7 minutes, until the spinach is fully integrated and the cheeses are melted and smooth.
Lightly mist a small baking dish with olive oil cooking spray.
Carefully spread the creamy spinach dip into the prepared baking dish, creating an even layer.
Sprinkle the remaining shredded mozzarella cheese generously over the top of the dip.
Preheat oven to 425°F (220°C). Place the dish in the oven and bake for approximately 10 minutes, or until the mozzarella cheese on top is perfectly melted and bubbly.
For an irresistibly golden-brown and slightly crispy cheese topping, you can broil the dip for an additional 1 to 2 minutes. Watch it very closely, as it will brown quickly!
Allow the dip to cool for a few minutes before serving. Serve warm with crunchy tortilla chips, toasted baguette slices, or fresh vegetable sticks.