In a large bowl, mix together flour, cornmeal, sugar, baking powder and pepper flakes.
Whisk together egg, milk, corn oil and corn. Pour liquid mixture over dry ingredients and stir lightly, using no more than 15-20 strokes to mix.
Generously butter twelve 2-1/2-inch muffin cups. Fill each muffin cup 1/2-full with batter. Reserve 1/3 of batter. With back of teaspoon, make small depression in center of each muffin and drop in 1 tsp. of jalapeño jelly.
Bake in preheated over at 375°F for 25 minutes or until light golden brown. Let muffins rest in pan for 2 minutes. Using blunt knife, ease muffins out onto wire rack and let cool for 20 minutes.