Heat the olive oil in a large, high sided pan on medium/high heat. Add in the beef, onion and garlic. Cook, breaking up the beef, until full cooked and no longer pink, about 5-7 minutes
Add in the broth, diced tomatoes, tomato paste, mustard, salt and pepper and stir until well mixed. Then, stir in the quinoa until well mixed.
Bring the mixture to a boil. Once boiling, cover the pan, turn to heat to low and cook until the quinoa absorbs the water and is creamy, about 1 hour.