Microwave 3 cups milk for 6 minutes in a glass measuring cup or small bowl. When done add 1/2 cup butter (1 cube) and 1 cup potato flakes to the hot milk and stir. Let sit for a few minutes while the butter melts and the potatoes absorb liquid.
While the milk is in the microwave put 1/4 cup warm water and 1 1/2 Tbsp yeast in a separate measuring cup and let sit. Do not stir. Set aside.
Using a stand mixer and the dough hook attachment, put the 4 eggs, 1 Tbsp salt, 3/4 cup sugar, 1/4 cup powdered sugar, and 1/4 cup butter in the mixing bowl. Mix for about one minute.
Add milk/potato mixture to the mixer on the lowest setting. Mix for about 30 seconds.
Add 4 cups flour to the mixing bowl one cup at a time and mix for about 30 seconds.
Add yeast/water mixture, then add 4 more cups of flour one cup at a time.
Knead on low speed for about 4-5 minutes. The dough is quite sticky and moist.
When done mixing the dough, spray a large metal or glass bowl with cooking spray and put the dough in the bowl to proof. Cover with a damp thin dish towel and let rise for about an hour. The dough will double in size.
When done proofing, sprinkle some flour on a clean surface. Cut dough into 4 sections. I usually do croissants so I roll the dough into a large circle about 1/4" thickness. Cut with a pizza cutter into triangles and roll up. Lay them on a greased cookie sheet. Let them rise for about 10-15 minutes and then bake at 350 degrees for 10-15 minutes until they start to lightly brown on top and bottom.