Grandmom's Cinnamon Rolls

Instructions

• Prepare dough: Heat milk in a saucepan over medium heat until just about to boil, 3 to 4 minutes. Add sugar, shortening, and salt; remove from heat and let cool to lukewarm, about 10 minutes.
• While the milk mixture is cooling, sprinkle yeast over water and let sit for 10 minutes.
• Pour lukewarm milk mixture into a bowl; add 1 cup flour and beat well. Beat in yeast mixture and egg. Gradually beat in remaining 2 1/2 cups flour. Cover and let rise until doubled in size, about 1 hour. Test by pressing a finger into the dough; a fingerprint should stay.
• Preheat the oven to 375 degrees F (190 degrees C). Grease two 9-inch square baking pans.
• Prepare filling: Mix sugar, melted butter, and cinnamon together in a bowl.
• Turn dough out onto a lightly floured board and divide in half. Roll one piece into a 16x8-inch rectangle. Spread 1/2 of the filling over top. Start at the long edge of the rectangle and roll up as for a jelly roll. Cut into eight 1-inch slices and place cut-sides down into one prepared baking pan. Repeat with remaining rectangle.
• Bake in the oven until golden brown, 20 to 25 minutes.
• Meanwhile, prepare frosting by mixing confectioners' sugar and water together in a bowl.
• Remove rolls from the oven. Transfer to a large serving plate and spread frosting over top.