6 1/4 oz. 7-grain hot cereal mix, 1 1/4 cups (Bob’s Red Mill or Arrowhead Mills brand)
20 oz. boiling water (2 1/2 cups)
15 oz. AP flour (3 cups), plus extra if needed
7 1/2 oz. whole wheat flour (1 1/2 cups)
4 Tbsp honey
4 Tbsp unsalted butter, melted and cooled slightly
2 1/2 tsp instant yeast
1 Tbsp table salt
3/4 cup pumpkin seeds or sunflower seeds (unsalted)
1/2 cup old-fashioned rolled oats or quick oats
Water or nonstick cooking spray
Place cereal mix in bowl of standing mixer and pour boiling water over it; let stand, stirring occasionally, until mixture cools to 100 degrees and resembles thick porridge, about 1 hour. Whisk flours in medium bowl.
Once grain mixture has cooled, add honey, melted butter, and yeast and stir to combine. Attach bowl to standing mixer fitted with dough hook. With mixer running on low speed, add flours, 1/2 cup at a time, and knead until dough forms ball, 1 1/2 to 2 minutes; cover bowl with plastic and let dough rest 20 minutes. Add salt and knead on medium-low speed until dough clears sides of bowl, 3 to 4 minutes (if it does not clear sides, add 2 to 3 tablespoons additional all-purpose flour and continue mixing); continue to knead dough for 5 more minutes. Add seeds and knead for another 15 seconds. Transfer dough to floured work surface and knead by hand until seeds are dispersed evenly and dough forms smooth, taut ball. Place dough into greased container with 4-quart capacity; cover with plastic wrap and allow to rise until doubled, 45 to 60 minutes.
Adjust oven rack to middle position; heat oven to 375 degrees. Spray two 9 by 5-inch loaf pans with nonstick cooking spray. Transfer dough to lightly floured work surface and pat into 12 by 9-inch rectangle; cut dough in half crosswise with knife or bench scraper.
With short side facing you, starting at farthest end, roll dough piece into log. Keep roll taut by tucking it under itself as you go. Pinch seam gently with thumb and forefinger. Spray loaves lightly with water or nonstick cooking spray. Roll each dough log in oats to coat evenly. Place loaf seam-side down in greased loaf pan. Cover with plastic wrap and let rise until almost doubled in size, 30 to 40 minutes. (Dough should barely spring back when poked with knuckle.)
Bake until internal temperature registers 200 degrees on instant-read thermometer, 35 to 40 minutes. Remove loaves from pans and cool on wire rack before slicing, about 3 hours.