In a blender blend together the cornmeal, the flour, the salt, the sugar, and the baking powder, add the water, the butter, and the egg, and blend the mixture for 15 seconds. Scrape down the sides, add the Cheddar, and blend the batter for 5 seconds, or until it is combined well. Spread 1/4 cup measures of the batter into 4-inch circles on buttered sheets and bake the crackers in batches in the middle of a preheated 400°F. oven for 6 minutes. Turn the crackers and bake them for 5 to 6 minutes more, or until they are crisp. The crackers keep in an airtight container for 1 week.
