In a large bowl, stir together the rolled oats, flour, baking powder, and salt. Add sourdough starter discard and melted butter and mix thoroughly.
Let the dough rest 10 minutes. Meanwhile, preheat the oven to 350°F (177°C), and line a half sheet baking pan with a Silpat silicone mat or parchment paper.
Roll the dough out to a 8- x 10-inch rectangle about ¼-inch thick and cut into 16 pieces. Alternately, roll out to a 8- x 9-inch rectangle, and cut into 12 pieces. Place on the half sheet baking pan.
Bake for 10 minutes, rotate the pan, then bake 10 to 13 minutes more.
Remove the pan to a wire rack to cool. Smear with your favorite condiment (I like butter & jam) and enjoy!
Recipe Notes
You can use oat flour instead of the rolled oats for a crispier bannock, as I learned later. To make your own oat flour, finely chop the rolled oats in a food processor.