Preheat your oven to 350 degrees F.Spray a loaf pan with cooking spray.In a stand mixer or large bowl, mix together the egg, egg whites, vanilla and stevia.Once combined, add in peanut butter and milk with an egg beater (if you don't have a stand mixer).Add in the oat flour, salt and baking powder to the same bowl. Mix until combined.** Skip this step if using a wheat flour with gluten.** Using your stand mixture or egg beater, mix together the batter for a full 1 minute on high. You want the mixture whipped really well to make it light and fluffy.Pour the batter into your loaf pan and bake for 40 minutes or until a toothpick comes clean.Allow to cool and cut into 13 slices. Store in an airtight container. Can be frozen.