Heat oven to 200C/fan 180C/gas 6. Steam the cauliflower for 4 mins until just cooked, then set aside. Heat the olive oil in a shallow casserole dish or flameproof roasting dish. Add the bacon and chilli powder and cook over a medium heat for 2-3 mins until the fat starts to run. Stir the cauliflower florets in with the bacon, then cook in the oven for 10-15 mins until the cauliflower has soaked up the chilli oil and is starting to brown.
While the cauliflower is roasting, cook the tagliatelle in boiling water according to pack instructions. Stir the cherry tomatoes in with the cauliflower, return to the oven and cook for about 2 mins until the tomatoes begin to soften.
Drain the tagliatelle, return to the pan, then mix in the bacon, cauliflower, tomatoes and half the basil. Serve the pasta drizzled with a little olive oil and scattered with the remaining basil.