For the jalapeños: Cut the tops off each jalapeño and carefully remove all seeds and membrane. Wrap each jalapeño tightly with a piece of bacon and fry in a cast-iron pan on medium-high heat, until the bacon has rendered and browned all around. Place on a cooling rack to cool completely.
Cut the cheddar cheese into equal-sized pieces small enough to fit inside each jalapeño. Stuff jalapeños with cheese.
For the cornbread batter: In a large bowl, combine the flour, cornmeal, sugar, salt and baking powder. In a separate bowl, whisk together the egg, milk and vegetable oil. Slowly incorporate the wet ingredients into the dry to form a smooth batter.
Grease a 5 1/2 by 9 1/2 inch loaf pan, and pour one-third of the batter in. Arrange the cooled jalapeños on the batter, and cover with the remaining batter.
Bake for approximately 1 hour or until a toothpick comes out clean when inserted into the middle. Allow to cool slightly before serving.