Whole Wheat Onion Hamburger Buns

1 cup lukewarm water
1/3 cup butter
1 egg
1/4 cup sugar
2 teaspoons minced onion
1 teaspoon salt 
1 tablespoon instant yeast
1 cup wheat flour
2 1/2 cups all-purpose flour
1 egg white
2 tablespoons water
sesame seeds/poppy seeds

In large mixing bowl, combine water, butter, egg, sugar, onion, salt, and instant yeast. Stir in wheat flour. Add all-purpose flour to form a ball. On floured surface, knead by hand for 5-6 minutes until dough is soft and smooth. Place in greased bowl, and cover. Let rise for 60-90 minutes until double in bulk. Punch down and divide into eight pieces. Shape each into a round ball. Place on lightly greased or parchment-lined baking sheet. Cover and allow to rise for 20-30 minutes while oven is preheating (375 degrees). To make egg wash, whisk egg white and water in small bowl and brush over each bun. Sprinkle each with sesame seeds and poppy seeds. Bake for 15-17 minutes until golden brown. Cool on rack and slice in half to serve. Makes 8 large buns.