Preheat oven to 375°F (190°C).
Brush a 24-cup mini muffin tin with melted butter.
Place one sheet of filo pastry on a clean surface and brush lightly with melted butter. Place another sheet on top and brush with butter again. Repeat until you have 3 layers of filo stacked.
Cut the stacked filo sheets into 24 squares approximately 4×4 inches each.
Gently press each filo square into the mini muffin cups to form cups. Repeat with remaining filo sheets and butter.
Bake the filo cups in the preheated oven for 7 minutes or until lightly golden and crisp. Remove from oven and set aside.
In a medium bowl, combine cream cheese, sour cream, mayonnaise, mozzarella cheese, Parmesan cheese, garlic, salt, and black pepper. Mix until smooth.
Fold in the chopped spinach and artichoke hearts until evenly combined.
Spoon about 1 tablespoon of the spinach artichoke mixture into each filo cup.
Return the filled filo cups to the oven and bake for an additional 8 minutes or until the filling is hot and bubbly.
Remove from oven and let cool for 2 minutes before serving.