These old-fashioned cinnamon rolls get their tenderness from the addition of shortening, sugar, and eggs to the dough.
Combine shortening, 1 cup sugar and salt in a large bowl; stir in 1 cup boiling water. Cool. Stir in eggs.
Combine yeast and 1 cup warm water in a 1-cup glass measuring cup; let stand 5 minutes. Stir into egg mixture. Gradually add flour, stirring until blended. Cover and chill at least 4 hours.
Roll one-third of dough into a 14- x 10-inch rectangle. Brush with 1/2 cup melted butter; sprinkle with 1/3 cup sugar and cinnamon. Roll up, starting at a long end; cut crosswise into 3/4-inch thick slices. Place in 2 lightly greased 9-inch round cakepans. Let rise and bake at 375° for 10 to 12 minutes or until golden. Stir together 1/2 cup powdered sugar and milk; drizzle glaze over warm rolls.