This is the step most people skip and then wonder why the pesto is clumpy and cold. Scoop out the pasta water before you drain — once it’s down the drain it’s gone. A few tablespoons stirred into the pesto warms it through and loosens it perfectly without cooking the basil.
Turning off the heat once the shrimp go in is not a mistake — it’s the technique. Boiling shrimp turns them rubbery fast. The residual heat of 6–8 quarts of near-boiling water is exactly enough to cook 21/25 shrimp gently in 3 minutes. Watch the clock.
This one comes together fastest as a two-person job: one cook handles the shrimp poach and peel while the other sautés the greens and gets the pasta going. Divide and conquer and it’s dinner in a fraction of the time.
The spinach-arugula mix wilts faster than you expect and keeps wilting after it leaves the heat. Add it to the bowl while it still has some body. By the time you’ve tossed everything together it will be perfectly soft without turning to mush.