The sourdough bread will have all einkorn flour EXCEPT for the flour you use in the starter. Your second option is to feed your starter several times with einkorn flour.
In a large, non-metal bowl, combine the starter with the warmed milk, water, and sugar. Add 2 ¾ cups of all-purpose einkorn flour and the salt. Stir just a couple of times with a very strong spatula. Gently add the melted butter or olive oil. Stir until the dough looks mostly wet.
Einkorn Sourdough Levain Weight Ingredient Baker's Percentage 39g Mature liquid starter (100% hydration) 4 100% 39g All-purpose einkorn flour (Jovial organi ... 100% 17g Water 45%