Optional fermentation step: A day or two before you plan to bake, stir the almond flour and kefir, whey, etc., together in a bowl. Cover and let sit for up to two days at room temperature.
When you are ready to bake, preheat oven to 375° F. Line a loaf pan with baking parchment along the length and brush with oil or melted butter.
Add the ingredients (minus the nuts or chocolate, if using) to the almond flour. Beat well until smooth, then fold the nuts and/or chocolate chips in.
Pour batter into prepared loaf pan and bake 45-55 minutes or until the loaf is browned, pulling away from the pan, and a toothpick inserted into it emerges with only a few crumbs.
After removing from the oven, cool for a few minutes, then carefully use the parchment to lift the loaf onto a cooling rack. You can remove the parchment when the loaf feels firm and unlikely to crumble. Slice and eat when cool, if you can wait!