Special equipment: a 12-cup standard muffin tin
Preheat the oven to 400 degrees F. Grease a 12-cup muffin tin with butter.
Whisk together the cornmeal, corn flour, baking powder and salt in a large bowl.
In a medium bowl, whisk together the eggs, milk and melted butter.
Add the wet ingredients to the dry ingredients and mix until just combined. Stir in the corn kernels and jalapenos.
Spoon a heaping 1/4 cup batter into each muffin cup. Bake until golden brown and an inserted toothpick comes out clean, 20 to 25 minutes.