Pound butter, garlic, lemon and basil in a mortar and pestle (or mash with a fork in a bowl) to combine well. Set aside.
- Cook pasta in a large pan of boiling salted water to packet instructions.
- Meanwhile, heat oil in a large, deep frypan over medium heat. Cook bacon, stirring, for 4-5 minutes until starting to crisp. Remove and drain on paper towel.
- Return pan to heat and melt half the butter. Add prawns and stir for 2-3 minutes until just cooked. Drain pasta, then add to frypan with bacon and remaining butter. Toss, season and serve with extra basil.