Place a medium saucepan over medium-high heat. Add the oil, then add the onions to the warmed oil. Saute, stirring often, for five minutes, until onions have softened slightly and started to brown.

Add the sage, pepper and mushrooms, and saute another five minutes, stirring occasionally.

Pour in some broth, and de-glaze the pan, scraping the bottom to loosen any cooked-on bits.

Stir in the orzo, then add the broth. Increase heat to high, bring to a boil, the reduce heat to low. Cover and allow to simmer for 10 minutes.

Remove from heat, stir in the nutritional yeast and let sit for five minutes. Fluff with a fork and serve immediately.