Position a rack in the center of the oven and preheat the oven to 375ºF. Line a dutch oven, a cast iron skillet, or a 9-inch baking pan with a sheet of parchment paper, set aside.

In the bowl of a stand mixer, combine 3 ¾ cups of flour, oats, baking soda, baking powder, garlic powder, salt, pepper, and sugar on the stir setting. Add the cold butter and let the machine break the butter down into small, pea-sized pieces. You can also do this by hand using a pastry cutter. Add the cheddar and chives, let the machine stir for just a few seconds until mixed.

In a large measuring cup, combine the egg and buttermilk. With the mixer on the stir setting, slowly pour in the wet ingredients until the dough comes together, about 30 seconds. If the mixture still looks super wet, add 2 tablespoons of flour and dump the dough out onto a well-floured surface. Use your hands to shape the dough into a large disk. If the dough is still wet, add the remaining 2 tablespoons of flour and shape it.

Place the dough on the prepared baking pan and cut an ‘x’ across the top, slicing about 1/2 way through the loaf. Bake for 50 minutes - 1 hour or until the bread is golden brown on top. Insert a skewer into the center of the bread and if it comes out clean, the bread is done. Let cool for 15 minutes before slicing.