Heat oven to 190C/fan 170C/gas 5. Halve the
tomatoes and arrange them in a single layer, cut
side up in a roasting tin.
To make the pesto: put the basil, pine nuts
and garlic in a food processor and whizz to
a paste. With the motor running, drizzle in
the oil. Transfer to a bowl, stir in the parmesan,
then season to taste. Spoon about 2 tsp pesto
over each tomato, then roast for 20 mins, until
the tomatoes are tender. Serve with grilled lamb
and a crisp green salad.