Preheat oven to 375°F (190°C). Grease a mini muffin pan.
Wilt the spinach in a skillet for 1–2 minutes. Let it cool slightly and squeeze out excess moisture.
In a bowl, combine ricotta, mozzarella, Parmesan, egg, garlic, Italian seasoning, salt, and pepper.
Stir in the spinach until evenly combined.
Spoon the mixture into the mini muffin cups, filling each about ¾ full.
Bake for 18–22 minutes, until golden and set.
Let cool for 5 minutes before removing from the pan.
Serve warm with marinara sauce for dipping.
