Mix cornmeal, baking powder, salt, and sugar in a medium bowl. Add in margarine and boiling water; mix well.
In a small bowl mix together the evaporated milk and vinegar. Stir milk and vinegar mixture into cornmeal mixture and mix well. Mix in egg.
Heat griddle or fry pan. (If electric fry pan is used, preheat it to 380 degrees.) Pan is "hot" when a drop of water "dances." Remove pan from flame and spray with nonstick cooking spray, return to stove.
Pour batter onto griddle or fry pan (1/4 cup measure is handy to use for pouring). Cook until top is covered with bubbles and the bottom is brown. Flip and cook on the other side. Be sure to thoroughly stir the batter up from the bottom now and then to keep it well mixed.