In a large bowl, add 2 cups flour, yeast, sugar, and salt. Whisk together.
In a microwave safe bowl, combine butter and water. Heat in microwave for 40-45 seconds. Butter will not be completely melted.
Pour the butter water mixture into the dry ingredients. Add egg and vanilla extract. Stir to combine.
Add remaining 2½ cups of flour, stir and mix well. Knead dough with clean hands, about 5-7 minutes.
Form dough into ball, place back into mixing bowl and let rise for 10 minutes.
Roll dough into a large 10 x 14 inch rectangle on a clean, well floured surface.
Spread softened butter over dough, leaving about one inch of the edges free from butter.
Next, sprinkle brown sugar evenly over the butter, followed by cinnamon.
Tightly roll, starting along the long side, into a log.
Using unflavored dental floss, cut the cinnamon roll dough into 1¼ inch circles (you can use a knife but floss is the best way to keep the "circular" shape).
Place each cinnamon roll in a 9x13 pan.
Place in a warm place, cover with a kitchen towel and let rise for an hour.
Preheat over to 350°.
Bake cinnamon rolls for 25-30 minutes or until they are light brown.
Remove from oven, set aside to cool until ready to add icing.
While cinnamon rolls are baking, prepare your icing.