Preheat the oven to 350 degrees Fahrenheit.
Add the almond butter, cocoa powder, maple syrup, plant-based milk, apple cider vinegar or lemon juice, vanilla extract, and salt to a large mixing bowl, then use a whisk to mix well.
Add the coconut flour, baking soda, and ground flaxseed to a separate bowl, then mix well.
Add the dry ingredients to the wet ingredients, then mix to combine.
Dip a pastry brush in oil to grease the donut pan (if you're using a silicone pan like I did then you can skip this step).
Transfer the batter to a large plastic resealable freezer bag and use scissors to snip off one corner of the bag (or use a piping bag if you have one).
Squeeze the bag to pipe the batter into eight slots in the donut pan (you may have to use two pans).
Wet your fingers with cold water, then smooth the surface of the batter so that it’s neat and even.
Bake at 350 degrees Fahrenheit for 27 minutes or until a toothpick inserted into a donut looks clean upon removal.
Let the donuts cool to room temperature before removing them from the donut pan.