Heat a non-stick skillet over medium heat 5 minutes. Melt 1 tbsp. margarine and add steak to pan, cook 10 minutes per side turning only once. Remove from pan and let rest while toasting bread.
While steak is cooking, thinly slice onion. Melt 1 tbsp. margarine in a small pan over medium heat, add onion and cook until golden brown, stirring occasionally.
While waiting for steak and onions to finish cooking, grate cheese and cut bread loaf into 5 pieces. Slice each bread serving in half lengthwise and spread remaining margarine over each piece. Remove steak from pan and use pan to lightly toast bread margarine side only.
Thinly slice the steak and place on bread with onions and cheese. Serve with French Fries (I used Alexia seasoned waffle) and pickle.