Braided Potato Bread

1 cup cooked mashed potato
2/3 cup milk
1/4 cup butter or margarine
3-1/2 cups all-purpose flour, divided
1/4 cup sugar
1 (.25-ounce) package active dry yeast
1-1/2 teaspoons salt
2 large eggs, at room temperature
1 egg white, lightly beaten
1 teaspoon water
2 teaspoons poppy seeds

Combine potato, milk and butter in a saucepan; heat until butter melts, stirring occasionally. Cool to 120 degrees to 130 degrees F (50 degrees to 55 degrees C). Combine 1-1/2 cups flour, sugar, yeast and salt in a large mixing bowl; stir well. Gradually add milk mixture and 2 eggs, beating at medium speed of an electric mixer 2 minutes. Stir in enough remaining flour to make a soft dough. Turn dough out onto a lightly floured surface, and knead until smooth and elastic, about 10 minutes. Place dough in a well-greased bowl, turning to grease top. Cover and let rise in a warm place (85 degrees F / 30 degrees C), free from drafts, 1-1/2 hours or until dough is doubled in bulk. Punch dough down; divide into 3 equal portions. Shape each portion of dough into a 14-inch rope. Place ropes on a greased baking sheet (do not stretch); pinch ends together at one end to seal. Braid ropes; pinch loose ends together to seal. Cover and let rise in a warm place, free from drafts, 1 hour or until dough is doubled in bulk. Combine egg white and water; stir well. Brush egg white mixture over top and sides of loaf. Sprinkle with poppy seeds. Bake at 350 degrees F (175 degrees C) for 30 to 35 minutes or until loaf sounds hollow when tapped. Remove bread from baking sheet immediately; let cool on a wire rack. Yield: 1 loaf