TO MAKE SPONGE: Mix flour, coconut sugar, milk kefir, and the sourdough starter together in a large mixing bowl with a wooden spoon. Cover (I use a plate) and let it rest on the counter overnight.
TO MAKE PANCAKE BATTER: In a small mixing bowl, beat the egg until foamy and fluffy. Beat in melted butter. Pour this into the bubbly sponge mixture and stir to combine. Add salt and baking soda, and stir in. The batter should start to puff up a bit. You may use this, or if you prefer slightly wetter batter, add a bit of milk.
Melt a little butter in a frying pan and when hot, spoon batter in. When the pancakes are full of bubbles, flip and cook reverse side lightly. They should come up golden brown!
Serve with fresh or stewed fruit, whipped cream, and REAL maple syrup!