Press GO to start step-by-step mode and keep your screen awake as you cook.
Step 1.
Bring a large pan of salted water to the boil and cook your pasta until al dente.
Step 2.
Grate the garlic clove into your food processor (it won't break down enough if you just blend it). Add the walnuts, reserving a few for garnish, and blitz until it resembles breadcrumbs.
Step 3.
Add the parsley, removing any big stalks, and 100ml of olive oil and blend until smooth.
Step 4.
Once the pasta is ready, drain and reserve a large mug of the cooking water.
Step 5.
Toss the pesto and pasta together along with the juice of the lemon, adding pasta water as you go until you have a smooth and creamy sauce.
Step 6.
Season with salt and pepper and plate up, finishing with a few more chunks of walnuts and a sprinkle of parsley.
