Preheat the oven to 200°C and line a baking tray with non-stick baking paper.
Place the passata, tomato puree and garlic granules in a small bowl and mix well.
Unroll the pastry sheet, leaving it on the greaseproof paper packing, and place it on a work surface. Spread the tomato mixture over the pastry sheet in a thin layer, leaving a 1cm gap along one long edge.
Sprinkle the Cheddar and Parmesan over in an even layer, leaving the 1cm gap along the long edge.
Spread the ham over the cheese in an even layer, leaving the 1cm gap along the long edge.
Spread the basil leaves over the ham, again leaving the gap along the long edge. Season well with salt and black pepper.
Roll up the pastry tightly, starting with the long edge without the 1cm gap and using the greaseproof paper to help you. Keep rolling it up until you have a 'Swiss roll'. When you have finished rolling the pastry, make sure it is seam-side down, then use a large, serrated knife (such as a bread knife) to cut it into 16 spiral-shaped slices.
Carefully transfer the slices to the lined baking tray, leaving gaps between each, and press the seam on each to ensure a good seal.
Bake in the preheated oven for 15-20 minutes, until golden and crisp. These swirls are best served warm, with your choice of accompaniment.