Start by combining butter and milk in a microwavable bowl, and then microwave for 1-2 minutes or until the butter has fully melted.
Pour in honey, yeast, oatmeal, all-purpose flour, salt, and whole wheat flour into the butter mixture. Mix them until combined then start adding the seeds (poppy, sesame, and sunflower).
Continue mixing the dough on low speed until it forms a soft dough.
If mixing by hand, remove the dough and place it on a lightly floured surface. Knead for about 8 minutes.
Place the dough in a greased bowl, turning once to coat the dough. Cover loosely with a clean cloth and let rise in a warm place for 1 1/2 to 2 hours or until doubled. Punch the dough down.
Add the dough onto the floured surface. Then flatten the dough into a rectangle, then fold a third of the dough on top of itself. Quickly fold the bottom third down so that it overlaps the other layers. Pinch the dough to seal where the layers meet to close it up.
Lift the dough and place it into a greased 9x5 inch loaf pan. Allow to rise for an additional 30 minutes or until the dough has risen 1 inch above pans.
Brush the dough with an egg wash and top it with additional seeds, if desired.
Bake at 350 degrees F (175 degrees C) for about 30-40 minutes or until the loaf is slightly golden brown on top and the loaf sounds hollow when tapped. If bread is browning too fast tent with foil paper.
Transfer pan to wire rack to cool for 10 minutes, then remove bread from pan and place on a wire rack to finish cooling.
Do not cut the bread before it has completely cooled.
Tightly wrap and store at room temperature or freeze for later use.