Preheat the oven to 400°F.
In a mixing bowl, combine the halved cherry tomatoes, olive oil, Tajin seasoning, garlic powder, oregano, salt, and pepper. Toss until the tomatoes are well coated.
On a lightly floured surface, roll out the puff pastry to smooth out any creases. Cut the pastry into 4 equal squares.
Place each square of puff pastry into a muffin tin, pressing gently to form a cup shape.
Sprinkle a layer of shredded mozzarella cheese at the bottom of each pastry cup.
Spoon the seasoned tomato mixture evenly into each pastry cup, filling them generously.
Brush the edges of the puff pastry with the beaten egg for a golden finish.
Bake in the preheated oven for 20-25 minutes, or until the pastry is puffed and golden brown.
Remove from the oven and let cool slightly. Top with fresh basil before serving.