In small bowl, dissolve 1 teaspoon sugar in warm water. Stir in yeast; let stand for 10 minutes, or until foamy.
In stand mixer bowl, combine 1/2 cup sugar, boiling water, rolled oats, cracked wheat, oil and salt; let cool to lukewarm (around 90-100°F). Stir in yeast mixture, flax seeds, sunflower seeds and eggs. Using a paddle attachment, blend on low speed for 30 seconds. Add whole wheat flour and 2 cups bread flour; beat on medium speed for 4 minutes.
Switch to dough hook attachment. Gradually stir in enough remaining bread flour to make a soft dough. Knead until smooth and elastic, about 7 to 10 minutes.(NOTE: For hand mixing: following above steps, mix ingredients in large mixing bowl using a wooden spoon or dough whisk. Knead on floured surface until smooth and elastic.)
Place dough in lightly oiled bowl and turn to grease top. Cover; let rise until indentation remains after poking dough with finger down to second knuckle, about 1 hour.
Grease two 8x4-inch loaf pans; set aside.
Punch down dough; turn out onto lightly floured surface. Divide dough in half; shape each portion into ball. Using rolling pin, gently roll each ball into a rectangle the length of loaf pan. Roll up into cylinder; pinch along bottom to seal. Fold each end of loaf in and pinch to seal. Place into prepared pans. Cover and let rise in warm draft-free place for about 1 hour or until doubled in bulk.
Preheat oven to 375°F.
Brush egg over loaves, sprinkle with topping of rolled oats and flax seeds. Bake in center of oven for about 30-35 minutes or until loaves are golden brown and sound hollow when tapped on bottom. Remove from pans; let cool on racks.