Combine all sauce ingredients in a small bowl and set aside.

Trim steak and cut into ¼ inch strips. Cut red pepper and onion into thin strips, and asparagus into 1 inch pieces.

Heat the peanut oil on medium high heat in a large skillet. Add steak strips a few at a time and brown on each side taking care not to overcrowd the skillet. Remove the browned strips to a plate while you finish cooking the remaining steak.

Add the bell pepper, onion and asparagus to the skillet and stir fry just until onion starts to become tender, about 2-3 minutes.

Return steak to skillet with the veggies and then pour in the sauce. Bring to a boil and cook for 1 minute.