Blanche the basil leaves in boiling water for 15 seconds and refresh in iced water. Drain the basil and dry on a clean tea towel to absorb any excess water. Pour 50ml olive oil into a blender and with the motor running, add the garlic and blend to a puree. Feed the basil into the blender. Pour in the remaining oil and continue to blend until smooth. Season to taste with salt, freshly ground pepper and a squeeze of fresh lemon. Pour the basil puree into a sieve lined with a double-layer of muslin cloth set over a bowl to collect the oil. When the oil has drained, discard the pulp. Store the basil oil in a sealed bottle and refrigerate until ready to use.