Preheat oven to 350 degrees.
Dissolve yeast in warm water. Scald milk and add to sugar, butter and salt; stir until butter is melted. Mix cinnamon and flour. Add 1/2 the flour to the milk/sugar/butter/salt, and mix until smooth. Beat 3 eggs and add them and the yeast to the mixture.
Continue to add remaining flour to make soft dough. Remove it from the bowl and place on floured board. Knead until smooth and satiny (about 15 mins.). Shape into a ball and place in buttered bowl. Cover and let rise until double in size (2-1/2 to 3 hours).
Punch risen dough down and divide it in half. Place in two greased pans (8 inches round). Let rise in warm place until double in size (1-1/2 to 2 hours). Brush tops of dough with remaining egg (beaten).
Bake in 350 degree oven for 20-30 minutes or until golden brown. Cool on wire racks.