‘Homegrown’ by Matt Jennings is a paean to the chef’s New England roots — with lamb meatballs

You could say that Matt Jennings has been following the chef’s playbook. He’s got four nominations for James Beard’s Regional Best Chef award (Northeast, for his former Providence, R.I., restaurant Farmstead and his Boston restaurant Townsman), four wins at the pig festival Cochon 555 and a pretty…