Line the bottom of an 8.5×4.5 glass loaf pan with parchment paper, then spread a very thin coating of coconut oil on the sides of the pan.
Beat the cashew butter with the egg yolks, then add the honey, vinegar, and milk. Both electric hand beaters and a stand mixer and both seem to work equally as well. Do not try to make this by hand due to the stickiness of the butter.
Beat the egg whites in a separate bowl until peaks form. Use an electric hand mixer or you can also do it by hand.
Combine the dry ingredients in another small bowl. Sorry for all of the dishes!
Make sure your oven is completely preheated before adding the egg whites and the dry ingredients to the cashew butter mixture. You don’t want your whites to fall, and the baking soda will activate once it hits the eggs and vinegar.
Pour the beaten egg whites into the cashew butter mixture, mixing until just combined. Make sure to get all of the sticky butter mixture off of the bottom of the bowl so you don’t end up with clumps.
Pour the dry ingredients into the wet ingredients, and beat until combined. This will result in more of a wet batter than a dough.
Pour the batter into the prepared loaf pan, then immediately put it into the oven.
Bake for 45-50 minutes, until the top is golden brown and a toothpick comes out clean. Don’t be tempted to open the oven door anytime before 40 minutes, as this will allow the steam to escape and you will not get a properly risen loaf.
Remove from the oven, then let cool for 15-20 minutes. Use a knife to free the sides from the loaf pan, then flip it upside down and release the loaf onto a cooling rack. Cool right-side up for an hour before serving.
Optional: Wrap the loaf up tightly and store in the fridge for 1 week.