Bring a large pot of salted water to a rolling boil. You’ll hear that deep, vigorous roar when it’s ready. Add the pasta shells and cook according to package instructions until al dente—usually around 10-12 minutes. Reserve a cup of the starchy pasta water before draining; that cloudy, pale liquid is liquid gold for the sauce.

While the pasta boils, start the sauce. In a large frying pan or skillet, melt the butter with the olive oil over a medium heat. You’ll see the butter foam slightly and release a nutty, warm aroma. Add the minced garlic and stir for about 30 seconds until it becomes fragrant but not coloured—you want it soft, not browned.

Add the lemon zest and juice. Sprinkle the bright yellow zest directly into the pan; the smell will immediately lift and sharpen. Pour in the lemon juice and watch it sizzle and steam. Stir everything together for a minute until the sauce looks glossy and smooth.

Pour in the double cream and stock. Whisk gently as the mixture comes to a gentle simmer. You’ll see the sauce thicken slightly and take on a pale, creamy yellow hue. Let it bubble softly for 2-3 minutes, stirring occasionally, until it coats the back of a spoon.

Add the frozen peas and protein (if using). Tip the peas straight into the pan—they’ll thaw and warm through in the heat of the sauce, turning a vibrant, bright green. If you’re adding cooked chicken, stir it in now so it can soak up the lemony butter.

Combine the pasta with the sauce. Drain the cooked shells and add them directly to the pan. Toss everything gently with a wooden spoon or spatula. You’ll see the sauce cling to every ridge and crevice of the shells, creating a beautiful, creamy coating. If the sauce seems too thick, add a splash of the reserved pasta water to loosen it.

Finish with Parmesan and parsley. Sprinkle in the grated Parmesan and stir until it melts into the sauce, adding a salty, savoury depth. Taste and adjust seasoning with salt and pepper. The texture should be silky, not runny, and the shells should feel luxurious as you stir them.

Serve immediately. Spoon the pasta into warm bowls, garnish with a little extra Parmesan and a sprinkle of fresh parsley. The steam will carry the lemon-butter scent right to your nose—a sign that the weekend project is complete.