Bring egg to room temperature by placing it in a bowl of warm water while getting ingredients together.
Never mix your salt & yeast together in the liquids. Doing so will usually kill your yeast.
In its own large bowl whisk together 4 of the 4 1/2 Cups of Flour and the salt. Set this Flour and salt mix aside. (Reserve the 1/2 cup of plain flour)
In a second bowl add the Warm Milk. The non-technical way of checking the temperature is to test on your wrist. Make it baby bottle warm. If you are the type that needs to use a thermometer the temperature should be on the yeast container, or you can find it on line. Many places state 110-115°F. Whisk Warm Milk, Agave, and Yeast together. Allow that is sit about 10-15 minutes to let the yeast "bloom".
Next crack the room temperature warmed raw egg into a third bowl and whisk well. Once well whisked, slowly pour the whisked egg into the Milk, Agave, Yeast mixture while whisking it in.
Lastly whisk the melted butter into the Milk mixture.
In a large bowl mix half the flour salt mix with the entire warmed milk yeast mixture. At this point you can use an electric mixer to help the dough along. This will be thin enough since only half the flour mixture is being blended in this step. You can also use the old fashion way of mixing it in the bowl by hand. A Kitchenaid with a dough hook is even better.
Or a Bread machine with the "Dough only option" could be used.
Using a bread machine you could set it to "Dough" and "Quick Bread" (since we are using rapid rise yeast) and dump all the Flour/Salt mix, and the mixed liquids together, turn the machine on, and walk away. Most machines that have a program cycle for quick dough will produce the dough in about 45 minutes. Complete with the first "raise". Ready to roll out and add the filling. Then raise the 2nd time.
For those using a more traditional methods read on.
Once the really thin mixture (Half the flour salt and all the liquids) have been mixed, slowly start adding the remaining flour/salt mix Toward the end, use that reserves ½ cup of the flour and adjust dough to proper consistency.
Kneading the Dough
Turn out on a floured board and knead and fold until proper dough consistency. Not sticky. And not dry and stiff. But stretchy and beginning to show signs of air bubbles. Some describe it as soft as a baby's bare bottom. The dough in this stage needs to be very well kneaded. It takes some time and work if doing it by hand.
Coat the well kneaded dough lightly with oil or butter (Pam or spray cooking oil is easiest), place in large warm raising bowl (a warmed heavy/thick glass or ceramic bowl works best). Cover the bowl with a towel or plastic wrap. Keep in a warm place for about 45 minutes. Dough should double. Punch down.
Adding the Sugar & Cinnamon Filling
Cut dough in half and work one half of the dough at a time to make rolls. On a floured board roll out dough, or work it by hand to about ¼ - ½ inch thick, in a rectangle about 16X20 inches. Spread with half the soft butter. Sprinkle with half the dough filling sugar mixture. Spread half the Raisins (optional) over the butter/sugar layer. Roll the dough up long ways so you have a log 20 inches long. Pinch the seam the length of the log. Slice across the log to make 12 equally wide rolls. Place the rolls in a warmed greased 11x15 baking dish. Or a greased warmed 12 inch Dutch Oven. Remember this is a double batch so you will need two baking dishes or two Dutch Ovens. Spray the tops lightly with Pam or other spray cooking oil. Repeat for the second half of the dough.
Second "Rise"Cover and keep in warm area for about 45-60 minutes or until doubled.
Preheat oven to 350° and Bake for 15-20 minutes or until slightly golden brown on the top. Properly baked they are soft but not under cooked and doughy. With a Dutch Oven and coals for 350° start checking them at 15 minutes, and then every 5 minutes until done. When removed from the oven brush the tops with melted butter.
Mix all icing ingredients using a hand mixer about the time the rolls come out of the oven. Add additional powdered sugar to get your desired consistency. I like little peaks that keep their shape. Spread icing on slightly warm rolls. If it is too thick add 1/4 teaspoon of milk and completely remix and recheck. Keep at room temperature to ice the rolls.
Let rolls cool slightly on a wire rack. While still warm spread half the mixture over each half batch of rolls.