In a large bowl, combine the starter with the warmed milk, water, and sugar. Stir to combine the starter and dissolve the sugar.
Add the 2 ¾ cups of all-purpose einkorn flour and salt. Stir a few times to combine the ingredients, then add olive oil. Stir until the dough looks mostly wet and is sticky.
Cover the dough with plastic wrap and place it in a warm place. Preferably 75°F or warmer. Let the dough rest undisturbed for 8-12 hours.
Line your loaf pan with parchment paper, pressing down the sides to fit the pan. Once the loaf is in there, the paper will stay down.
Generously flour your surface and your hands (the dough will be sticky). Scoop the dough out of the bowl directly onto the floured surface. Sprinkle at least ¼ cup of flour on top of the dough.
Fold the dough over in thirds. You can use a Dough Scraper to unstick the dough. Rotate the dough 90 degrees to the left and fold in thirds again, adding flour as needed to keep the dough from sticking to the surface. Rotate the dough 90 degrees to the left one more time and fold in thirds again, adding flour as needed to keep the dough from sticking to the surface.
Preheat the oven to 425°F.
Place dough in the prepared loaf pan. Cover the loaf pan with a towel or plastic wrap and let it rise until the dough has risen a little in the pan, approximately 30-60 minutes. It doesn't need to rise all the way - just so it's rising.
Place the loaf pan in the oven and immediately reduce the temperature to 375°F.
Bake the bread for 40 minutes. When the bread is ready, let it cool in the loaf pan for 15-20 minutes on a wire rack.