In a separate bowl, dissolve yeast in warm water. Sprinkle a spoonful of the sugar on top of the yeast.

In a larger bowl, stir milk, sugar, yeast mixture, mashed potatoes, salt, eggs, Crisco and 3 cups of the flour. Add enough flour to make the dough easy to handle.

Turn out dough onto a lightly floured surface and knead until smooth and elastic (about 5 minutes).

Place the dough in a large bowl and cover. Let rise in a warm place until the dough has doubled in size (about 1 1/2 hours).

Punch dough down. Divide dough in half, and roll each half into a rectangle.

Spread each rectangle with butter.

In a small bowl, combine the brown sugar, granulated sugar, and cinnamon. Sprinkle sugar mixture over to dough rectangles.

Beginning at the wide side of the rectangle, roll up the dough. Pinch the edge of the dough into a roll to seal well.

Cut each roll into individual rolls using thread of dental floss. (These will make a cleaner cut than a knife.)

Place each cinnamon roll onto a greased baking pan and let rise until the rolls have doubled in size.

Bake cinnamon rolls at 400 degrees F for approximately 10-12 minutes.

Using an electric mixer, blend together butter and sugar. Stir in vanilla and milk and beat until frosting is smooth and of spreading consistency.

Frost the cinnamon rolls while they are still warm.