Quinoa-Stuffed Acorn Squash with Figs and Sage

medium-sized acorn squash

olive oil + extra for roasting squash

uncooked quinoa

vegetable stock or broth

chopped yellow onion (I used 1 small onion from our CSA)

small stalk celery, thinly sliced (about 1/2 cup)

figs, stems trimmed off and quartered

heaping 1/2 Tbsp minced fresh sage leaves

balsamic vinegar

balsamic reduction for drizzling (optional)