Preheat oven to 350 degrees. Heat oil in a saucepan and add onion and quinoa. Saute over medium heat, stirring constantly for 3 minutes. Add red bell pepper and saute an additional 2 minutes. Add water, soy sauce and rosemary. (If using fresh peas, add them now.)

Bring contents to a boil; cover and simmer 15 minutes.

Meanwhile, roast walnuts in 350 degree oven for 5 minutes. When quinoa is cooked, turn off heat and mix in walnuts and frozen peas. Let set an additional 10 minutes and serve.