I have enjoyed the dishes in Nigella Kitchen which use baby squid, but find that it is only stocked by a limited number of fishmongers. Would it be ok to substitute for full sized squid?
Nigella uses baby squid in her recipes for Korean Calamari, Quick Calamari Pasta, Roast Seafood and Squink Risotto. All of these recipes use the squid sliced into rings, except for the Roast Seafood.
Where the squid is sliced into rings it is possible to use regular squid and the cooking time will be pretty much the same. The main advantage of using baby squid is that they are usually more tender than the larger ones. The tentacles on larger squid are going to be larger than the baby version, so it is a good idea to cut the tentacles from larger squid into bite-sized pieces so that they cook quickly.
It is also possible to use frozen squid rings instead and sometimes the freezing process can help to tenderize the squid. When using frozen squid rings we would suggest that they are thawed overnight in the refrigerator before using.
Nigella has several other recipes using baby squid, including Salt And Pepper Squid (see link), that you may like to try.