1. Stir together the flour, sugar, salt, yeast, and cinnamon in a mixing bowl (or in the bowl of an electric mixer). Add the egg, shortening, buttermilk, and water. Stir together with a large spoon (or mix on low speed with the paddle attachment) until the ingredients come together and form a ball. Adjust with flour or water if the dough seems too sticky or too dry and stiff.
2. Sprinkle flour on a counter, transfer the dough to the counter, and begin kneading (or mixing on medium speed, switching to the dough hook). The dough should be soft and pliable, tacky but not sticky. Add flour as you knead (or mix), if necessary, to achieve this texture. Knead by hand for approximately 10 minutes (or by machine for 6 to 8 minutes). Sprinkle in the raisins and walnuts during the final 2 minutes of kneading (or mixing) to distribute them evenly and to avoid crushing them too much. (If you are mixing by machine, you may have to finish kneading by hand to distribute the raisins and walnuts evenly.) The dough should pass the windowpane test and register 77 to 81 degrees F. Lightly oil a large bowl and transfer the dough to the bowl, rolling it to coat it with oil. Cover the bowl with plastic wrap.
3. Ferment at room temperature for approximately 2 hours, or until the dough doubles in size.
4. Divide the dough into 2 equal pieces and form them into loaves. Place each loaf in a lightly oiled 8½ by 4½-inch pan, mist the tops with spray oil, and cover loosely with plastic wrap.
5. Proof at room temperature for 60 to 90 minutes, or until the dough crests above the lips of the pans and is nearly doubled in size.
6. Preheat the oven to 350 degrees F with the oven rack on the middle shelf. Place the loaf pans on a sheet pan, making sure they are not touching each other.
7. Bake the loaves for 20 minutes. Rotate the pan 180 degrees for even baking and continue baking for another 20 to 30 minutes, depending on the oven. The finished breads should register 190 degrees F in the center and be golden brown on top and lightly golden on the sides and bottom. They should make a hollow sound when thumped on the bottom.
8. Immediately remove the breads from their pans. Mix together the granulated sugar and ground cinnamon for the topping in a shallow plate. Brush the tops of the loaves with melted butter as soon as they come out of the bread pans, and then roll them in the cinnamon sugar. Cool loaves on a rack for at least 1 hour, preferably 2 hours, before slicing or serving.