Divide dough into 18 portions as above. Roll pieces into balls, placing 9 each in two greased 9 by 5-inch loaf pans. Increase baking time to 18 to 20 minutes.
Pat dough and cut squares as for Lemon Brioche. For each bunny, remove a tiny bit from a square and shape into a 1/4-inch ball for a nose. Shape remaining piece into an oval, about 3 inches long and 2 1/4 inches wide. Using kitchen shears or a dough scraper, make a 2-inch cut lengthwise down the center of the oval (you’ll go about two-thirds of the way) to make the bunny’s ears. Pinch dough oval where the cut stops to define the head (head might seem small but will become bigger during rising and baking). Gently shape head. Using the side of your pinky, make indentations in the ears. Make a small indentation in the center of the head with your finger, brush with water, and add the small ball for the nose. Let rise, brush with egg white mixture, and bake as directed for Lemon Brioche.