In a small bowl, combine the yeast with the warm water and let it sit until the yeast becomes active (it should appear foamy). In a large bowl, pour the milk over the brown sugar, salt and shortening or butter. Cool to lukewarm. Beat in 3 cups of the flour and all of the eggs. Stir in the yeast, currants and oats. Add just enough more flour to make a stiff dough. Turn out onto a lightly floured board and knead until smooth and silky, about 10 minutes. Place in a well-greased bowl and let rise until double in bulk (about 1 hour). Divide the dough into two parts. Let the dough rest for 10 minutes.
Combine 1/3 cup sugar and cinnamon. Roll each half of the dough into an 8x15-inch rectangle and spread each with half the sugar-cinnamon mixture. Roll each to form a loaf and place in a greased 5x9-inch loaf pan, seam side down.
Brush the loaves lightly with melted butter, cover and let rise in a warm place until doubled, about 1 hour.
Preheat the oven to 400 degrees F. Bake the bread for 10 minutes. Reduce the oven temperature to 375 degrees and continue baking for 25 to 30 more minutes. Cool on racks.