1 1/4 cups all-purpose flour
1 1/4 cups whole-wheat flour
1 1/4 cups cornmeal
1 1/4 cups old-fashioned rolled oats
1/2 cup toasted wheat germ
1/2 cup packed light brown sugar
1 tablespoon baking powder
1 1/2 teaspoons salt
1 1/2 sticks (3/4 cup) cold unsalted butter, cut into tablespoon pieces
1 cup plus 1 tablespoon water
1/2 cup chopped fresh flat-leaf parsley
1/2 cup chopped fresh mint leaves
1 large egg
Special equipment: a pastry or bench scraper; a dog-biscuit cookie cutter
Pulse flours, cornmeal, oats, wheat germ, brown sugar, baking powder, and salt in a food processor until combined. Add butter and pulse until mixture resembles coarse meal with pea-size butter lumps. Add 1 cup water and pulse until a coarse, dense dough forms.
Turn out onto a lightly floured surface and knead in parsley and mint until well distributed. Gather, then halve dough with scraper. Form into 2 balls and flatten each into a 6-inch disk.
Put oven racks in upper and lower thirds of oven and preheat oven to 350°F. Grease 2 large baking sheets.
Roll out 1 disk of dough into a round (1/3 inch thick) on a well-floured surface with a well-floured rolling pin. (If dough becomes too soft to roll out, wrap in plastic and chill until firm.) Cut out as many biscuits as possible and arrange about 1/4 inch apart on 1 baking sheet.
Gather scraps and reroll, then cut out more biscuits. Repeat with remaining dough, using other baking sheet.
Whisk together egg and 1 tablespoon water. Brush biscuits with egg wash and bake, switching position of sheets halfway through, until tops are golden brown, about 35 minutes total. Turn off oven and dry biscuits in oven overnight.
Biscuits keep, layered between sheets of wax paper or parchment, in an airtight container at room temperature 1 month.
Servings: Makes about 5 dozen biscuits.