To make dough: In large bowl, combine 1 cup flour, 1/2 cup sugar, undissolved yeast and salt. Heat 1/2 cup butter, potatoes, milk and water until very warm (120 to 130ºF); stir into dry ingredients. Stir in eggs and enough remaining flour to make soft dough. Knead on lightly floured surface until smooth and elastic, about 4 to 6 minutes. Cover; let rest 10 minutes.

To shape and fill: Roll dough to 15 × 9-inch rectangle; brush with 1 tablespoon melted butter. In small bowl, combine 1/4 cup sugar, cocoa and cinnamon; sprinkle evenly on dough to within 1/2 inch of edges. Beginning at long end, roll up tightly; pinch seam to seal. With sharp knife, cut roll into 12 equal pieces. Place, cut sides up, into 12 greased (2 1/2-inch) muffin cups. Cover; let rise in warm, draft-free place until doubled in size, about 45 to 60 minutes.

Bake at 375ºF for 15 to 20 minutes or until done. Remove from cups; cool on wire racks. Lightly sift powdered sugar over tops.