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. If the dough seems too sticky or dry, adjust with flour or water by adding in a very small amount until incorporated.
Sprinkle flour on a counter, transfer the dough to the counter and begin kneading or mixing on medium speed (if using electric mixer, at this time switch 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 (see testing note in description above for a fully developed dough).
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. Allow to rise at room temperature for approximately 2 hours or until the dough doubles in size.
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.
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.
Preheat the oven to 350 degrees with the oven rack on the middle shelf. Place the loaf pans on a sheet pan, making sure they are not touching each other.
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.
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.