Heat vegetable oil in a saucepan on medium high heat. Stir fry diced yellow onion until fragrance. Pour in the rest of diced carrot, jicama, Chinese mushroom, and minced fungus. Stir fry for 3 minutes or until all the vegetables are just tender. Then add peas, if using, and pour vegie ground beef. Pour in the sauce and stir fry for 1 minutes. Finally, add green onion and corn starch. Mix up and remove from heat. (Sprinkle about 1/2 tsp. ground pepper, if desired.) Set aside.