1. Soak 1/3 cup bulgur in 1/2 cup warm water for 20 minutes; set aside. Sprinkle yeast over 1/2 cup water. Add 2 teaspoons honey. Whisk until yeast dissolves. Let stand until foamy, about 5 minutes. Transfer to the bowl of a mixer fitted with the paddle or dough-hook attachment. Add butter and remaining 1 1/2 cups water and 3 tablespoons honey. Whisk flour with salt; add 3 cups to yeast. Mix on low speed until smooth. Mix in soaked bulgur, 1/2 cup rolled oats, 1/4 cup flaxseeds, and 1/4 cup raw sunflower seeds. Add remaining 4 cups flour, 1 cup at a time, mixing until dough comes away from sides of bowl and forms a ragged, slightly sticky ball. Butter a large bowl.

2. Knead dough on a floured surface until smooth and elastic but still slightly tacky, about 5 minutes. Shape into a ball. Transfer to prepared bowl; cover with plastic wrap.

3. Let dough stand in a warm place until it doubles in volume (it should not spring back when pressed), about 1 hour. Butter two 4 1/2-by-8 1/2-inch loaf pans. Punch down dough; divide in half.

4. Shape 1 dough half into an 8 1/2-inch-long rectangle (about 1/2 inch thick). Fold long sides of dough in to middle, overlapping slightly. Press seam to seal. Transfer dough, seam side down, to pan. Repeat with remaining dough. Brush tops of loaves with egg wash (beaten egg white mixed with water), not butter, and sprinkle with oats and sunflower seeds. Dab tops with egg wash to help adhere. Preheat oven to 450 degrees. Drape loaves with plastic. Let stand until dough rises about 1 inch above tops of pans, 45 minutes to 1 hour. Reduce oven temperature to 400 degrees. Bake, rotating pans after 20 minutes, until tops are golden brown, about 45 minutes. Transfer to wire racks. Let cool slightly; turn out loaves. Let cool completely before slicing.