Preheat the oven to 220C/450F/Gas 7. Line a baking tray with baking parchment.
Roll out the puff pastry onto a lightly dusted work surface. Cut four circles from the pastry using a cookie cutter. Prick each pastry circle several times using a fork.
In a bowl, mix together the chopped spinach, cheddar, nutmeg and ready-made ratatouille until well combined.
Place two of the pastry circles onto the lined baking tray. Spoon half of the filling mixture into the centre of both pastry circles.
Dab a little water around the edge of both pastry circles using a pastry brush. Place one of the remaining pastry circles over each, pressing down at the edges to seal.
Sprinkle each pasty with a little water, then top with a little more grated cheddar.
Bake the pasties in the oven for 12-15 minutes, or until the pastry has risen and is golden-brown. Set aside to cool slightly before eating with a tomato salad.