For the pastry:
Put the flour in a mixing bowl and stir in the salt. Rub in the butter with your fingers until the mixture resembles breadcrumbs. Stir in the egg and mix with your hands to form a dough. If the mixture is too dry, add a little water, if it is too wet add a little more flour. Shape into a ball. Wrap in cling film and chill in the refrigerator for about 30 minutes.
Heat the oven to 200°C (180° fan) 400°F gas 6. Brush 4 mini tart or quiche tins with oil or melted butter.
Divide the dough into 4 equal portions. Roll out 1 piece of dough on a floured surface until it is larger than the diameter of the tin.
Gently roll the pastry around the rolling pin. Unroll the pastry on top of the tart tin, then use your hands to lower the pastry into the corners of the tin, pressing it into the edges. Repeat with the remaining portions of dough.
Prick the bases of the pastry cases with a fork and bake for about 10 minutes until golden. Take out of the oven while you make the filling.
Turn the oven down to 180°C (160° fan) 350°F gas 4.
For the filling:
Mix together the tomatoes, spring onions, peas and chives. Spoon the vegetable mixture into the pastry cases.
Whisk the eggs in a large jug and stir in the cheese and cream. Season to taste with salt and pepper.
Pour the cheese and cream mixture over the vegetables and bake for 25-35 minutes until the filling is set. Serve warm or cold.