Preheat your waffle iron. If desired, preheat oven to 200 degrees Fahrenheit to keep waffles warm until you're ready to serve.In a medium-sized mixing bowl, whisk together the buckwheat flour, sugar, baking powder, baking soda, salt and cinnamon.In a liquid measuring cup or another bowl, whisk together the buttermilk, melted butter and egg. Pour the wet mixture into the dry mixture and stir them together until there are only a few small lumps remaining. Give it a few more stirs if you see any liquid that hasn't fully incorporated.Pour batter onto the hot waffle iron plates, close the waffle iron and cook until the waffles are barely letting off steam and they are lightly crisp to the touch. Carefully lift waffle out of the waffle iron and serve immediately or place in the oven to keep warm. Avoid stacking the waffles or they will lose their crispness. Repeat with remaining batter as necessary. Serve with maple syrup, almond butter and/or sliced banana on top.