Microwave milk for 1 minute (or warm it via stovetop)
Pour yeast into milk, stir once and then let it sit for 5 minutes, or until the yeast foams/bubbles slightly on top
Combine flour, whole wheat flour, oats, salt and flax seed (in a stand mixing bowl or a larger bowl) and stir to combine
In a small bowl, combine butter and honey. Melt in microwave
Pour in honey/butter mixture into the milk/yeast mixture. Then pour the liquid into the large bowl with the dry ingredients
Using a dough hook, knead bread for 5 minutes. If you're not using a mixer, knead with hands (about 5-10 minutes). The texture should be springy to touch, but not too sticky.
Transfer to a lightly oiled bowl, so the mixture doesn't stick to the sides of the bowl
Cover bowl with towel or plastic wrap and let it rise for one hour
After the mixture bulks up and doubles in size, pick up the dough and form it into a log. Place dough into a greased 9x5 loaf pan.
Cover with plastic wrap lightly and allow to rise for another hour until it has risen to the top of the loaf pan.
Preheat oven to 350 degrees
Bake at 350 for 35 - 40 minutes
Poke a toothpick or fork in the center of the bread and make sure it comes out clean to ensure it is cooked
Remove from the oven and turn loaf out onto cooling rack so it doesn't sink
Allow to cool and enjoy!