Melt butter and set aside to come to room temp. I melted my butter right in the pan I planned on cooking the pancakes in. Then when I dumped out the butter it left the plan nice and greased.
Mix ground flax seed with warm water and set aside to thicken.
In a large bowl whisk together buckwheat flour, potato starch, baking powder and salt and set aside. You can use a spoon but I find the whisk works well to break up any clumps.
Mix together the milk, vanilla, sugar, cooled melted butter and flax egg.
Make a well in the center of the dry ingredients and pour in the wet ingredients. Use a spoon or rubber spatula to mix together. Mix only until combined, you don't want to over mix pancake batter. Some lumps won't kill you. While you are doing this step heat a nonstick pan over medium heat and grease.
Cook the pancakes in the center of the pan. You want the pan warm enough to cook them quick but not too hot where they are burning. Flip the pancakes once the sides looked cooked. Then only cook the other side until center is no longer wet.