Combine 2 cups flour, 1/2 cup sugar, salt, and yeast; stir well. Combine milk, 1/4 cup butter, and potato in a saucepan; heat until butter melts, stirring occasionally. Cool to 120° to 130°. Add liquid mixture to flour mixture, beating at low speed of an electric mixer. Beat an additional 2 minutes at medium speed. Add 3/4 cup flour, beating 2 minutes at medium speed. Stir in enough of the remaining 2 1/4 cups flour to make a soft dough.
Sprinkle 1/4 cup flour over work surface. Turn dough out; knead until smooth and elastic (about 8 minutes). Place in a greased bowl, turning to grease top. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until doubled in bulk.
Punch dough down; roll to a 24- x 6-inch rectangle. Brush with melted butter. Combine 1/2 cup brown sugar and cinnamon; sprinkle over dough. Roll up, starting at long side. Pinch seam to seal (do not seal ends). Cut into 16 (1 1/2-inch) slices.
Spoon remaining 1 1/2 cups brown sugar into a greased 13- x 9- x 2-inch baking dish. Sprinkle pecans over sugar. Place slices over sugar. Pour whipping cream around rolls. Cover and let rise in a warm place, free from drafts, 30 minutes or until doubled in bulk. Bake at 350° for 30 minutes or until done. Let cool 2 minutes.