Combine the flour, cornmeal, sugar, baking powder, and salt in a large bowl. In separate bowl, combine the milk, eggs, and butter. With a wooden spoon, stir the wet ingredients into the dry until most of the lumps are dissolved. Don’t overmix! Mix in 2 cups of the grated Cheddar, the scallions and jalapenos, and allow the mixture to sit at room temperature for 20 minutes.