Heat the oil in a large saucepan on medium-high heat. Place the beef in the pan and brown for about 5 minutes. Add the onion, carrots and celery. Cook until the onion is opaque, about 10 minutes. Add the quinoa and beef broth.
Make a bouquet garni (bundle of herbs) by placing the rosemary, thyme, bay leaf and parsley in a small 4-inch (10 cm) square piece of cheesecloth and tying it with a cotton string. (You can also use a tea strainer or simply tie the herbs together with a string.) Immerse the bundle in the soup.
Simmer the soup for about 20 minutes, until the quinoa is tender. Add the potatoes and peas in the last 10 minutes of cooking. Remove the fresh herbs, season with salt and pepper and serve.