Cook the pasta in boiling salted water for 6-8 minutes, or until al dente. Reserve 1 cup of cooking water before draining the pasta.
Preheat the grill to high. Combine the chickpeas, harissa, honey and tomatoes in a large roasting tray. Add the pasta and reserved cooking water, and gently toss together. Spoon over the yoghurt and butter, then stir to combine.
Place under the grill for 6 minutes, or until starting to char and crisp. Scatter with pine nuts and basil, drizzle with oil and serve.
