In a measuring cup, combine milk and apple cider vinegar. Set aside to curdle.

In a large bowl, combine the ground flax with 3 tablespoons water. Allow to sit for a few minutes to thicken.

Pour the almond milk mixture into the bowl with the flax and stir to combine. Add the buckwheat flour, coconut sugar, cinnamon, baking powder, baking soda and salt (in that order). If using oil, add it now. Use a spatula to fold the ingredients together until evenly combined. Allow to sit for 5-10 minutes while you heat up the waffle maker.

Lightly grease the waffle maker then pour in enough batter to cover 3/4 of the bottom. For me this is about 1 cup. Close and cook for about 5-7 minutes on each side, or until the edges are golden brown and crispy. The time and serving size will vary depending on your waffle maker.

Serve warm with fruit and/or melted nut butter, and pure maple syrup. Leftovers can be refrigerated for up to 3 days or frozen for up to 1 month. Place in toaster or oven to reheat when ready to eat.