Preheat the oven to 200°C/fan180°C/gas 6.
Unroll the puff pastry, then trim to a 30cm x 20cm rectangle and score a 2cm border around the edge.
Prick the pastry, around the centre of the pastry all over with a fork.
Place on a baking sheet and bake in the oven for 15 minutes.
Slice the tomatoes and arrange over the pastry.
Scatter the Gorgonzola and sprinkle with Thyme leaves.
Return to the oven for 10 minutes.