Roll out the pastry on a lightly floured surface to a round about 5cm larger than a 25cm tin. Use your rolling pin to lift it up, then drape over the tart case so there is an overhang of pastry on the sides.
Using a small ball of pastry scraps, push the pastry into the corners of the tin. Chill in the fridge or freezer for 20 mins. Heat oven to 200C/fan 180C/gas 6.
In a small roasting tin, drizzle the tomatoes with olive oil and season with salt and pepper. Put the tomatoes in a low shelf of the oven.
Lightly prick the base of the tart with a fork, line the tart case with a large circle of greaseproof paper or foil, then fill with baking beans. Blind-bake the tart for 20 mins, remove the paper and beans, then continue to cook for 5-10 mins until biscuit brown.
When you remove the tart case from the oven, take out the tomatoes, too.
While the tart is cooking, beat the eggs in a large bowl. Gradually add the cream, then stir in the basil and season. When the case is ready, sprinkle half the cheese over the base, scatter over the tomatoes, pour over the cream mix, then finally scatter over the rest of the cheese.
Bake for 20-25 mins until set and golden brown. Leave to cool in the case, trim the edges of the pastry, then remove from the tin. Scatter over the remaining basil and serve in slices..