Pulse oats, egg whites, and cottage cheese in a blender for about 10 seconds, then let sit 15-20 minutes to hydrate.
Mix honey with warm water, add yeast, and wait 5 minutes until foamy.
Add soaked oats, butter, and salt to yeast mixture; stir in bread flour to form shaggy dough.
Knead dough 6-8 minutes with a dough hook or 10-12 by hand, adding extra flour as needed until dough is soft and pulls from sides.
Let dough rise in a warm spot until doubled, then shape into a log, place in a greased loaf pan, and let rise until it crowns the rim.
Preheat oven to 350°F, brush top with beaten egg, and bake for 60-75 minutes until internal temp reaches 190°F. Cool completely before slicing into 10 slices.
Notes
Ensure the dough is slightly wet for a soft crumb, and avoid slicing warm to prevent gumminess.