Boil the spaghetti according to pack instructions
and, when you have just 2 mins cooking time left,
throw in the peas.
Meanwhile, whisk the olive oil, lemon juice and
mustard together, then season with salt, if you
like, and pepper. Drain the pasta, reserving
a couple of tbsps of the cooking water and
return to the pan. Stir the reserved cooking
water, olive oil mixture and mint through the
pasta, then serve.