In the bowl of a stand-mixer, whisk together the flour, ground flaxseeds, milk powder, baking soda, baking powder, salt, and yeast.
Add the honey, apple cider vinegar, avocado oil, eggs, and kombucha. Start the stand-mixer on low until the ingredients are starting to combine, then increase the speed to medium-low and allow the stand-mixer to mix the dough for 5 minutes.
Meanwhile, lightly oil an 8x4 or 9x5 loaf pan with coconut oil OR line the pan with unbleached parchment paper. Once the dough has been mixed, scrap the dough into the loaf pan and gently smooth out the top, shaping the dough into a rounded load in the pan.
Cover the pan with some plastic wrap and place the pan in a warm location to proof for 30 minutes. If you kitchen is on the cool side, allow it to proof for 40-50 minutes.
About 10 minutes before the loaf is done proofing, preheat the oven to 350℉. Once the loaf has proofed, bake it for 50-60 minutes. The top should be golden brown and the internal temperature should read at least 210℉.
Transfer the loaf pan to a cooling rack and cover the loaf pan with a light towel. Allow the bread to cool for 20-30 minutes, then remove the loaf from the pan and allow it to cool completely but keep it covered with the towel.
You can slice the bread after 1 hour of cooling, but make sure the loaf is completely cool before keeping it stored in an airtight container.
This loaf is best enjoyed within 2-3 days of baking. But you can keep the loaf stored in an airtight container at room temperature for up to 5 days, in the fridge for up to 7 days, or the bread can easily be frozen.