To keep the cakes warm and crisp, transfer them to a rack on a baking sheet, and place the sheet in a 200° oven until serving time.
Heat the oil in a small skillet over medium heat. Add the corn, bell pepper, and jalapeno, and cook 10 minutes, stirring occasionally. Remove from heat, and stir in the scallions. Set aside.
Combine the flour, cornmeal, baking powder, soda, and salt in a large bowl.
Whisk the buttermilk and eggs until smooth. Pour the buttermilk mixture into the flour mixture, and stir until just combined. Fold in the corn-pepper mixture.
Heat a small nonstick skillet coated with cooking spray (or a little butter) over medium heat. Spoon about 1/3 cup batter into the hot skillet. Turn the pancakes when the tops are covered with bubbles and the edges are browned. Cook about 30 seconds until well-browned. Serve warm with sour cream, if desired.