This is the fastest proper dinner I know. By the time the pasta water has boiled and the linguine is cooked, the sauce is done — garlic softened in butter and oil, prawns cooked in barely two minutes, a big hit of lemon, and a splash of the starchy pasta water to bring it together into a glossy, clinging sauce.
The two things that make or break it: don't overcook the prawns (they go from tender to rubbery in about a minute), and use enough pasta water. That cloudy water is what turns melted butter and oil into a sauce rather than a puddle.
Parsley and chilli are optional but both belong. Serve immediately — this does not wait.
Bring a large pan of well-salted water to the boil. Add the linguine and cook to the packet time, minus 1 minute. Reserve a large mug of pasta water before draining.
While the pasta cooks, heat the butter and oil in a large frying pan over medium heat. Add the sliced garlic and chilli flakes and cook gently for 1–2 minutes until the garlic is soft and pale gold — do not let it brown.
Turn the heat up to medium-high. Add the prawns in a single layer and cook for about 1 minute each side, until just pink and opaque. Season with salt and pepper.
Add the drained linguine to the pan with the lemon zest, lemon juice and a good splash of the pasta water. Toss hard over the heat for a minute, adding more water a little at a time, until the sauce turns glossy and coats the strands.
Off the heat, stir through the parsley. Taste and adjust the lemon, salt and pepper. Serve immediately, twirled into bowls, with an extra grind of black pepper.
Prawns: Raw, peeled king prawns are best. If using frozen, thaw fully and pat very dry or they'll steam. Cooked prawns work in a pinch — add them at the very end just to warm through.
Pasta water: Salt it well and reserve a full mug before draining. You'll use more than you expect.
No linguine: Spaghetti or tagliatelle are fine. Avoid short shapes — this sauce wants long strands.
Make it richer: A tablespoon of crème fraîche stirred in at the end.