Preheat oven to 375 degrees then line a baking sheet with parchment paper and spray lightly with cooking spray. In a large bowl, sift together flour, sugar, baking soda, baking powder and salt. NOTE: We strongly recommend you weigh your einkorn flour, if possible, for better accuracy. If you don’t have a scale, fluff the flour with a fork before you measure it in a cup.
In a separate smaller bowl, combine buttermilk with beaten egg. Make a well in the center of dry ingredients and pour buttermilk and egg mixture along with the melted butter into the well and stir just until a ball of dough forms.
Form dough into a cohesive ball and place on prepared baking sheet. Pat dough into about an 8"–9" round loaf (the loaf will be 3"–4" thick in the center). Use a sharp knife to cut an X into the top of the dough.
Combine 2 Tbsp melted butter with 2 Tbsp buttermilk and brush entire amount onto the dough, covering the entire loaf. Bake 40–50 minutes or until a toothpick comes out clean. Remove from oven and cool until warm or room temperature, slice and serve.