Preheat oven to 400 degrees
Begin by combining 3 tablespoons olive oil along with the onions, green pepper, & celery in a large skillet. Cook while peeling and dicing the sweet potatoes
Add the sweet potatoes to the skillet and place in the oven for 20-25 minutes stirring occasionally
While the vegetables are cooking, brown the ground turkey, drain, and set aside
In a small bowl combine the sage, rosemary, salt, pepper, and 1 tablespoon olive oil
Once the sweet potatoes are tender, add the ground turkey and seasonings to the skillet, stir thorougly and return to the oven for about 5 more minutes
