Spread evenly the button on the baguette. Toast it to make it crispy.
Marinade the beef with the seasoning for 15 mins. Heat the pan with 1 tsp oil over high heat. Pan fry the beef until both side is golden, about medium done. Put it aside.
Heat the pan with medium high heat. Add in 1 tsp of oil. Add in the onion, shallots, and garlic. Stir fry them until fragrant.
Add in Group A sauce mixture. Turn the heat to low and stir fry it a bit. Add in the Group B sauce mixture and bring it to boil. Add enough starch mixture to thicken the sauce.
Add in the beef and peanut butter. Put the satay beef mixture into the baguette. Enjoy.