To make the cakes: Heat the oil in a medium skillet over medium-high heat. Add the corn, shallot, jalapeno, and 1/2 teaspoon of salt, and cook, stirring, until the corn is tender and fragrant, about 3 minutes. Set aside to cool.
In a medium bowl, whisk the buttermilk and egg. Stir in the cooled corn mixture.
In another medium bowl, whisk together the remaining 1/2 teaspoon salt, cornmeal, flour, baking powder, soda, and cayenne. Add the buttermilk mixture and stir to form a thick batter (take care not to overmix). Set batter aside while making the confit topping.
To make the topping: In a small saucepan, whisk together the demi-glace and jelly and cook over medium heat until just thickened. Add the duck and diced peppers and cook, stirring occasionally until heated through. Add the Essence and set aside, covered, while you make the corncakes.
Place a paper towel-lined baking sheet in the oven and preheat to 100 degrees F.
Preheat a large skillet over medium heat. Pour in enough of the vegetable oil to lightly film the skillet. Add about a tablespoon of the batter at a time, being careful not to overcrowd the pan. Cook until golden brown, turning once, about 2 minutes per side. Using a slotted spatula, transfer the corncakes to the baking sheet to keep warm. Repeat with the remaining batter to make about 30 corncakes in all.
To serve, place the warm corncakes on a serving platter and top each with some of the duck mixture. Garnish each corncake with a cilantro leaf and serve.
Yield: about 30 hors d'oeuvres