In a 9-inch cast-iron skillet, combine the pancetta, olive oil and butter and cook over medium heat until the pancetta is nice and crispy, about 5 minutes. Remove from the heat and allow the skillet to cool for 10 minutes.
Meanwhile, mix the flour, cornmeal, sugar, baking powder, baking soda and salt in a medium bowl; set aside.
In a large bowl, combine the buttermilk and eggs and whisk until smooth. Slowly drizzle the pancetta renderings into the egg mixture, whisking constantly, until all the oil is added. Add the pancetta that didn't fall into the egg mixture to the bowl and stir to combine. Add the dry ingredients to the egg mixture and stir with a rubber spatula until a thick batter forms. Pour the batter into the same skillet used to cook the pancetta. Cover the skillet with a double layer of aluminum foil.
Place the skillet over medium heat if using the stove top (or on indirect heat if working on a campfire) and cook until the sides are golden and a toothpick inserted into the center comes out clean, 20 to 30 minutes. Allow to cool for 10 minutes before serving.
You can also bake the cornbread at 350 degrees F until cooked through, about 30 minutes.