Heat oven to 200C (190C fan forced)

Line a baking tray with a sheet of baking paper. Lay the sheet of pastry onto the baking paper. Leaving a border of 3cm, spread the mustard over the pastry. Sprinkle the parmesan over the mustard. 

Cut the tomatoes in half and place them on top of the parmesan, cut side up. Season with salt and cracked black pepper.

Roll the 3cm border of the pastry up, forming a tart edge. Brush the edges of the pastry with the melted butter. Drizzle the olive oil over the tomatoes. Bake in the centre of the oven for 20 – 25 minutes until the pastry edges are golden brown. 

Top with fresh whole basil leaves and serve.