In a big bowl, mix 2 cups of flour with the yeast and salt.
In a small saucepan, warm the milk, sugar, and butter until the butter melts and it feels warm (about 115 degrees).
Pour the milk mixture into the flour mixture, add the beaten egg, and beat with an electric mixer on low for 30 seconds.
Scrape the sides of the bowl and then beat on high for 3 minutes.
Add enough of the remaining flour to form a soft, non-sticky dough.
Put the dough on a floured surface and knead for about 8 minutes until it's smooth and stretchy. Alternatively, you can use a heavy-duty electric mixer with a bread hook for about 4 minutes.
Grease a bowl lightly, put the dough in it, and turn it once to coat the surface of the dough. Cover and let it rise in a warm place until it's about twice its size, which takes about 1 1/2 hours.
After it rises, punch the dough down, put it on a floured surface, and cover it with a towel for 10 minutes.
For the Filling:
Mix together the white sugar, brown sugar, and cinnamon.
Coat a 9-by-13-inch baking dish or a cookie sheet with approximately 2 tablespoons of melted butter.
Roll out the dough into a rectangle about 12 by 20 inches in size.
Brush the dough generously with the remaining melted butter and sprinkle it with the sugar-cinnamon mixture.
Roll the dough up from a short end to make a log that's about 12 inches long.
Cut the log into 1-inch-wide rolls.
Place the rolls in the buttered pan with the cinnamon side up. Drizzle any leftover butter on top.
Cover them and let them rise for about 30 minutes until they're puffy and touch the sides of the pan and each other.
Preheat your oven to 375 degrees.
Baking:
Bake the rolls for around 30 minutes, until they turn lightly golden brown.
Let them cool in the pan for 10 minutes.
For the Glaze:
While the rolls are cooling, mix the confectioners' sugar, vanilla extract, and milk to make the glaze.
Drizzle the glaze over the warm rolls.
Enjoy your homemade Knaus Berry Farm cinnamon rolls!