Udon noodles are a type of wheat noodle often used in Japanese cuisine.
Combine mustards, sugar, soy sauce and miso paste for the sauce/marinade. Divide into 2 equal parts.
Marinate ground or sliced beef with half, Set other half of sauce aside.
In a non-stick pan, toast sesame seeds until golden brown over medium heat. Set aside.
Toast mustard seed until it starts popping. Set aside.
Cut green onion diagonally into 1 inch pieces. Set aside.
Add canola oil to pan. Sauté onion, garlic and ginger for 1 minute.
Stir in marinated beef and cook until the beef is done, about 2 minutes. Set aside.
Add button mushrooms, udon noodles and remaining sauce. Toss carefully to combine. Cook until noodles absorb most of the sauce and are completely heated through.
Turn off heat and add in cooked beef, toasted sesame seeds, toasted mustard see and green onion (garnish).
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.