Dissolve yeast in warm water. Stir in bananas, 1/4 cup sugar, salt, egg, butter and 1-3/4 cups of the flour. Beat until smooth. Stir in enough remaining flour to make dough easy to handle. Turn dough onto lightly floured surface; knead until smooth and elastic (about 5 minutes). Place in greased bowl; turn greased side up. Cover; let rise in warm place until double, about 1-1/2 hours.

Grease well 9 x 5 x 3 inch loaf pan. Punch down dough. Roll into rectangle, 16 x 8 inch. Mix 1/4 cup sugar with the cinnamon and sprinkle over the rectangle of dough. Roll dough up tightly, beginning at narrow side. Pinch edge of dough into roll to seal well. Place seam side down in pan. Cover; let rise until double(about 1 hour).

Heat oven to 375 degrees. Bake until golden, about 35 minutes. Remove from pan, and brush top with butter. If desired, can be frosted with a confectioners' sugar glaze.