In a medium bowl, combine the warm water (1 1/4 cups) and honey (2 tbs). Sprinkle the active dry yeast (2 tsp) over the surface, stir gently, and let sit for 5–8 minutes until foamy. If mixture does not foam after 10 minutes, discard and start with fresh yeast.

Combine wet ingredients

Whisk together the milk (1/2 cup), melted butter (2 tbs), and the lightly beaten egg (1) in a separate bowl. Once the yeast is foamy, add the milk-butter-egg mixture and stir to combine.

Mix dry ingredients

In the bowl of a stand mixer fitted with a dough hook (or a large mixing bowl if kneading by hand), whisk together the bread flour (2 cups), whole wheat flour (1 cup), rolled oats (1/2 cup), multigrain cereal blend (1/2 cup), vital wheat gluten (1 tbs, optional) and salt (1 1/2 tsp) to evenly distribute ingredients.

Form the dough

Add the wet mixture to the dry ingredients. Mix on low speed until ingredients come together (about 1–2 minutes). Increase speed to medium-low and knead for 6–8 minutes until the dough is smooth, elastic, and slightly tacky. If dough is too sticky, add up to 2 tbs more bread flour, a tablespoon at a time. If too dry, add up to 1–2 tbs warm water.

First rise

Lightly oil a large bowl and transfer the dough, turning to coat. Cover the bowl with plastic wrap or a damp towel and let rise in a warm draft-free place until doubled in size, about 60–75 minutes (time will vary with room temperature).

Shape the loaf

Punch down the risen dough gently to release gas. Turn it out onto a lightly floured surface and pat into a rectangle roughly the width of your loaf pan. Shape the dough into a tight loaf by folding short ends into the center and rolling to fit a standard 9x5-inch (23x13 cm) loaf pan. Tuck ends underneath for a neat loaf.

Second rise

Lightly grease the loaf pan and place the shaped dough seam-side down. Cover loosely with greased plastic wrap or a damp towel and let rise until the dough reaches about 1 inch above the rim of the pan, about 45–60 minutes. Meanwhile, preheat the oven to 375°F (190°C) during the last 15 minutes of the second rise.

Topping / Finishing

Prepare steam and egg wash

When the dough has nearly completed its second rise and the oven is preheating, place a shallow metal baking tray on the bottom rack of the oven. Measure 1/2 cup water for steaming and set aside. Beat 1 egg with 1 tsp water to make the egg wash.

Apply egg wash and seeds

Once the dough has risen to the correct height, gently brush the top with the egg wash, being careful not to deflate the dough. Sprinkle the remaining 1 tbs rolled oats or mixed seeds evenly across the top.

Bake with steam

Place the loaf on the middle rack. Carefully pour the 1/2 cup water into the preheated shallow tray on the bottom rack to create steam (do this quickly to retain oven heat). Close the oven and bake for 30–35 minutes, rotating the pan halfway through if your oven bakes unevenly. The loaf is done when the crust is deep golden brown and an instant-read thermometer inserted into the center reads 190–200°F (88–93°C).

Cool the loaf

Remove the loaf from the oven and immediately transfer it to a wire rack. Let cool in the pan for 10 minutes, then gently remove the loaf from the pan and cool completely on the rack for at least 1 hour before slicing. Cooling prevents a gummy crumb.