Add the herbs, capers, garlic, anchovy paste, chilli flakes, black pepper, olive oil and vinegar into a small bowl and stir together with a spoon.
2 tablespoons chopped parsley, 1 tablespoon chopped basil, 1 tablespoon chopped capers, 1 tablespoon red wine vinegar, 1 clove garlic, ¼ teaspoon anchovy paste, ¼ teaspoon red pepper flakes, ¼ teaspoon freshly ground black pepper, 3 tablespoons extra virgin olive oil