Bake, grill or air-fry the meatballs, following the instructions on the packet.
Cook the pasta according to the instructions on the packet.
Meanwhile, make the pea and watercress sauce.
Chop the garlic cloves.
Heat the oil in a pot, then fry the garlic for 30 seconds.
Add the peas and the sock then bring to the boil.
Cook for 5 minutes over low heat, then add the watercress and nuts (if used) and turn off the heat.
Using a stick blender, whiz until you get a smooth sauce.
Add the cider vinegar and taste. Adjust the seasoning to your liking.
When the pasta is ready, drain, then add to the sauce.
Toss well.
Serve the pasta with the meatballs and a squeeze of lemon.