In a small saucepan, melt the butter over low heat. Remove from heat and stir in the milk until warm.

In a bowl, combine the melted butter and milk with honey, warm water, and yeast. Mix until just combined.

In a separate bowl, stir together the whole wheat flour, all purpose flour, and kosher salt. Add dry ingredients to the wet mixture and stir until just combined.

Attach the dough hook to a stand mixer and knead on medium-low speed for 8 minutes. Alternatively, knead by hand for 8 minutes until the dough feels pillowy and smooth.

Shape the dough into a boule by folding it under itself using floured hands.

Place the dough ball in a clean bowl, cover with a dish towel, and let rise at room temperature for 1 hour until puffy.

Grease an 8-inch or 9-inch loaf pan. Turn the dough onto a floured counter and press into a rectangle about 1/2-inch thick. Roll into a log, pinch seams, and place seam-side down in the greased pan.

Cover the bread pan with a dish towel and let it proof at room temperature for another 1 hour until puffy.

Preheat the oven to 350°F.

After the second rise, brush the top of the loaf with water and sprinkle with chopped oats if desired. Bake for 35 to 37 minutes until golden brown and the internal temperature reaches 190°F.

Remove the bread to a cooling rack and cool completely for at least 90 minutes before slicing.