Variations:
This also works well with green beans (especially with penne) instead of or as well as the peas. If using frozen green beans just add them to the pan a few minutes earlier to allow for their slightly longer cooking time.
Pesto traditionally contains Parmesan cheese but there are several dairy-free brands on the market - try Zest, Meridian, or Sacla free-from, or our family favourite Le Conserve della Nonna. They're all quite different from one another so try several to discover which one you prefer. Dried pasta is usually vegan, but beware of fresh pasta as it tends to contain egg.