For the dough:
½ cup oat bran
¼ cup flax seeds
½ cup boiling water
1 cup warm milk (105-110˚ F)
2¼ tsp. instant (rapid rise) yeast
¼ cup honey
2 large eggs
2/3 cup old-fashioned (not instant) oats
7 oz. (1¼ cups) whole wheat flour
1 tsp. freshly ground black pepper
1 tbsp. salt
15 oz. (about 3 cups) all-purpose flour
Oil, for greasing the bowl
For the topping:
1 large egg yolk
1 tbsp. water
2 tbsp. mixed seeds (poppy, sesame, fennel, etc.)
Coarse salt, for sprinkling
Combine the oat bran and flax seeds in a small bowl. Pour the boiling water into the bowl and mix to moisten. Let sit until the water is absorbed, about 5 minutes. Set aside to cool. Meanwhile, in the bowl of an electric mixer, combine the milk, yeast and honey; mix briefly to blend. With the dough hook and the mixer on low speed, mix in the eggs, oats, wheat flour, pepper, salt and oat bran mixture until combined. Slowly add enough all-purpose flour, ½ cup at a time, to make a soft, slightly sticky dough. Continue to knead on medium-low speed, about 3 minutes.
Form the dough into a ball. Transfer the dough to a lightly oiled bowl, turning once to coat. Cover with plastic wrap or a clean kitchen towel and let rise in a warm place until doubled in bulk, about 1½-2 hours.
Brush a baking dish lightly with oil (I used a 10-inch round baking dish). On a lightly floured surface, turn the dough out and divide into 16 equal pieces, about 2½ ounces each. Form each portion into a ball and place the dough balls in the baking dish, spaced slightly apart so they have room to grow together. Cover and let rise until puffy and nearly doubled in bulk, about 30 minutes.
Preheat the oven to 375˚ F. In a small bowl whisk together the egg yolk and water. Brush lightly over the proofed rolls. Sprinkle the unbaked rolls with the seed mixture and coarse salt. Bake until the tops are golden, about 26 minutes. Let cool 10-15 minutes before removing from the pan.