Preheat the oven to gas 7, 220°C, fan 200°C. Arrange the asparagus in a roasting tin in a single layer and drizzle over the olive oil. Season well, then roast in the oven for 15 minutes, or until the asparagus is just tender.
Meanwhile, mix all the dip ingredients in a bowl until well combined. Cover and chill until needed. Top with a little extra shredded basil and serve alongside the warm roasted asparagus for dipping, or put the spears on a serving plate and drizzle it over.