Soften the Oats:
In a large bowl, combine oats, butter, salt, and honey (or sugar). Pour the boiling water over and stir. Let sit for 20–25 minutes until lukewarm.

Activate the Yeast:
In a small bowl, dissolve yeast in the warm water. Let it sit for 5–10 minutes until foamy.

Make the Dough:
Add the yeast mixture to the cooled oat mixture. Stir in 2 1/2 cups of flour until a sticky dough forms. Add more flour, 1 tablespoon at a time, if needed.

Knead the Dough:
Turn onto a lightly floured surface and knead for 6–8 minutes until smooth and elastic.

First Rise:
Place the dough in a greased bowl, cover, and let rise in a warm place until doubled—about 1 hour.

Shape and Second Rise:
Punch down the dough and shape into a loaf. Place in a greased 9×5-inch loaf pan. Cover and let rise again until it domes about 1 inch above the pan—about 30–45 minutes.

Bake:
Preheat oven to 350°F (175°C). Bake for 35–40 minutes until golden brown and the loaf sounds hollow when tapped. (Internal temp should be ~190°F.)

Cool:
Remove from pan and let cool completely on a wire rack before slicing.