Preheat your oven to 400°F (200°C) and prepare a large baking sheet with parchment paper.
Shape the mozzarella into 8 circles on the sheet, ensuring space between them for expansion.
In a skillet over medium-high heat, cook the ground sausage until fully browned, then drain excess fat.
Lower the heat, add the onion and garlic, and sauté until the onion is tender.
Mix in the cream cheese until melted, then add the spinach and cook until wilted.
Remove from heat and let cool.
Bake the cheese circles for 8 minutes or until the edges are golden.
Once slightly cooled, place filling in the center of each cheese circle and fold to create roll-ups.
Allow to cool and crisp before serving.