Lamb and Butternut Squash Stew (with homemade Lamb Stock)

olive (or vegetable) oil, as needed

~1 pound lamb shoulder, in 1-inch cubes

kosher or sea salt

freshly ground black pepper

small onion, roughly chopped

large carrot, scrubbed and cut into 1/2-inch circles (or half moons if really large)

fat cloves garlic, peeled and smashed

petite diced tomatoes, with the juices

lamb stock (see below)

few sprigs fresh thyme

large sprig fresh rosemary

small butternut squash, cut into ~1/2-inch chunks (2 heaping cups cut)

finely grated zest of a lemon, to serve

fresh parsley, to serve