Make dough as directed in recipe. Lightly grease cookie sheet with shortening or spray with cooking spray. After pushing fist into dough, divide into 3 equal parts. Roll each part into 14-inch rope. Place ropes close together on cookie sheet. Braid ropes gently and loosely, starting in middle; do not stretch. Pinch ends; tuck ends under braid securely. Brush with vegetable oil. Cover loosely with plastic wrap and let rise in warm place 40 to 50 minutes or until dough has doubled in size. Heat oven to 375°F. In small bowl, mix 1 egg yolk and 2 tablespoons water; brush over braid. Sprinkle with poppy seed. Bake 25 to 30 minutes or until golden brown.
Braid ropes gently and loosely, starting at the middle; do not stretch.