1. In a small pan over low heat, warm milk, butter and honey until butter has melted and an instant-read thermometer reads 110ºF. In a large bowl, whisk together whole-wheat flour, 1 cup bread flour, yeast and salt. Stir in milk mixture. Beat with a wooden spoon until a soft dough forms, adding more bread flour as needed. Dough will be sticky. Turn out onto a floured surface and knead until smooth and elastic, about 10 minutes, adding additional bread flour as necessary to keep dough from sticking. Cover dough with a cloth and let rise for 15 minutes.
2. Mist a 12-cup muffin tin with cooking spray. Divide dough into 12 pieces. Working with 1 piece at a time and keeping others covered with the cloth, divide into 3 even pieces. Roll each piece into a ball and put into a muffin cup side by side to make 1 cloverleaf roll. Repeat with remaining dough. Cover with a cloth and let rise for 15 minutes.
3. Preheat oven to 425ºF. Brush dough with egg mixture and sprinkle with seeds, if desired. Bake until golden brown, 10 to 12 minutes. Remove from pan and serve.