1) Preheat the oven to 260°C/gas mark 10.
2) Pour the 2 tablespoons of olive oil onto a baking sheet and place the red peppers, cut side up, on the oil. Turn the peppers over, season them with salt and pepper, and roast in the oven for 20 minutes.
3) Place the warm red peppers in a bowl, and cover with cling film. set aside to cool for at least 30 minutes.
4) For the basil oil, put the basil, olive oil and the garlic into the bowl of a food processor fitted with a steel blade. Pulse 6 to 8 times until the basil is finely chopped.
5) When the red peppers are cool, remove and discard the skins, then slice.
Arrange the red peppers on a plate. Pour over the basil oil and garnish with the basil leaves.