Mix the einkorn flour, baking powder, baking soda, and kosher salt together in a bowl. In another bowl, mix the buttermilk, honey, eggs, vanilla, and melted butter.
Make a well in the middle of the dry ingredients. Pour the wet ingredients inside the well and slowly incorporate the dry ingredients. Don't overmix. Stop once all the flour has been incorporated.
Warm up 1 tablespoon of butter in a cast iron pan until most of the bubbles disperse. On low to medium heat, use a ladle to pour in 1/3 cup of batter to make 1 pancake. In a 12 inch cast iron skillet, you can fit 2-3 pancakes.
After 2 minutes, or once the underside starts to turn golden, flip the pancakes. Cook each pancake another 1 minute or until the other side turns golden.
Melt a tablespoon of butter in the skillet before cooking each set of pancakes.
Top the pancakes with strawberry and rhubarb compote and softened butter. Bon Appetit!