1. Put the flours, yeast, sugar, baking powder and salt in a bowl. Make a well in the center and pour in 1 cup of hot water. Knead until the dough is smooth, 8 minutes. Cover and let rise in a warm place for 30 minutes.
2. Preheat the oven to 425ºF. Knead the dough again and divide into 10 equal pieces. Roll each piece into a 15-inch long rope.
3. Fold the dough into a pretzel by making a U-shape, crossing the ends over each other and pressing them back on the U-shape. Sprinkle the dough with water if it gets too dry. Place shaped pretzels on a parchment-lined baking sheet.
4. Separate the egg and reserve the white for another use. In a small bowl whisk the yolk and brush on the pretzels. Sprinkle with coarse salt and let the pretzels rise for another 10 minutes. Bake on the middle rack of the oven until golden brown, 15 minutes.
Per serving: 154 calories, 1g fat, 0g saturated fat, 25mg cholesterol, 897mg sodium, 31g carbohydrate, 2g fiber, 1g sugar, 5g protein