Whole-Grain Challah

Ingredients

• 1 ½ tablespoons dry active yeast
• ½ teaspoon sugar
• 1 ¼ cups lukewarm water
• 2 ½ cups unbleached bread flour (preferably King Arthur)
• 1 ½ cups whole-wheat bread flour (can also use regular whole-wheat flour)
• ½ cup oat bran
• 1 ½ teaspoons salt
• ½ cup sugar
• ¼ cup vegetable oil
• 2 large eggs
• 1 egg yolk (or I whole egg)
• 1 teaspoon water
• ¼ cup whole oats (optional)
• 2 tablespoons whole flaxseed (optional)
• ¼ teaspoon coarse sea salt (optional)
• ¼ cup sunflower seeds (optional)
• ¼ cup sliced almonds (optional)