Prepare the Dough:

1. In a small cup, add yeast, milk, butter and sugar, and whisk to combine. Let it sit for 5 minutes to activate the yeast.
2. In a large mixing bowl, whisk to combine all purpose flour, whole wheat flour, 1/3 cup oats, cranberries, flaxseeds, sesame seeds and salt.
3. Pour in the yeast mixture, and stir with a silicone spatula to combine until it forms a shaggy dough, scraping down the sides of the bowl (there should be no dry flour particles visible).
4. Transfer the dough onto a clean surface and knead for 5 minutes until it turns into a smooth dough ball. Because of the medium hydration (60% flour to liquid ratio) and high fat content (butter and milk), the dough is much softer and is easy to knead into a smooth ball.
5. Drizzle and spread a little bit of oil over the dough with your hands to help prevent it from drying out. Cover the bowl with plastic cling wrap and let it sit at room temperature for up to 2 hours or until doubled in size.

Shape the Dough:

1. Transfer the dough onto a lightly oiled surface. Flatten the dough into 9x5-inch rectangle and roll it into a log. Pinch the edges together to seal.
2. Transfer the rolled dough into a 9x5 loaf pan and press it down with your palm to spread cover the entire pan. This also helps distribute air bubbles evenly in dough when it rises. Set it aside to rise until the loaf almost rises to the rim of the pan, about 1-1.5 hours.

Add Toppings and Bake:

1. Preheat the oven to 400F.
2. Gently brush egg wash over the top crust (be gentle with brushing since the loaf is filled with air bubbles). Sprinkle the top with the remaining oats and poppy seeds.
3. Bake for 40 minutes until the top turns golden brown.
4. Allow loaf to cool in the pan for 5 minutes, then remove out of the pan and cool completely on a wire cooling rack before slicing, about 1 hour.