1. Combine yeast and warm water in a bowl (either from a mixer or large free-standing bowl). Allow to bloom for 5 minutes, then whisk until smooth. Whisk in 1/2 cup flour and cover with a towel. Allow to sit in a warm spot for 30 minutes.
2. Add eggs, sugar, salt, and remaining 4 cups of flour to the yeast mixture. Knead with a dough hook on medium speed for 4 minutes, or until smooth if mixing by hand. Add room temperature butter and continue to knead for 10-12 minutes, or until the dough is smooth. Add a little flour to reduce stickiness, if needed. Cover with a towel and let rise in a warm spot until doubled in size, approximately 2 hours.
3. Butter a 9×13 inch baking dish. Transfer the dough to a floured surface and, using a rolling pin, roll out into a 15×10 inch rectangle. Brush the rectangle with half of the melted butter, leaving a 2-inch wide strip unbrushed on one long side. Sprinkle the cinnamon sugar over the butter. Starting at the long side covered with sugar, roll up the rectangle snugly and pinch the seam together. With the seam facing down, cut dough into 10 equal pieces**. Place the pieces cut side up in the dish and brush the tops with the remaining butter. Cover with plastic wrap and let the rolls rise in the refrigerator overnight.
4. The next morning, remove the cinnamon rolls from the refrigerator and let rise until half again as high, about 1 hour. Preheat the oven to 350 degrees. Bake until golden brown, about 30 minutes. Let cool in the baking pan for 15 minutes. Spread optional glaze over the warm rolls and enjoy!

Vanilla Glaze Instructions

1. In a small bowl, sift sugar and salt. In a separate bowl, whisk butter, milk and vanilla. Stir into the sugar to form a smooth paste. Spread over warm cinnamon rolls.