In a small bowl, dissolve yeast in warm water. In a large bowl, combine mashed potatoes, sugar, butter, eggs, salt, yeast mixture and 2 cups flour; beat on medium speed until smooth. Stir in enough remaining flour to form a soft dough.
Turn dough onto a floured surface; knead until smooth and elastic, 6-8 minutes. Place in a greased bowl, turning once to grease the top. Cover and let rise in a warm place until doubled, about 1 hour.
For topping, in a small saucepan, melt butter. Stir in brown sugar, honey and cinnamon. Divide mixture among 3 greased 9-in. round baking pans, spreading evenly. Sprinkle with walnuts.
For filling, in a small bowl, mix sugar and cinnamon. Punch down dough. Turn onto a lightly floured surface; divide in half. Roll 1 portion into an 18x12-in. rectangle. Brush with 1 tablespoon melted butter to within 1/2 in. of edges; sprinkle with 1/4 cup sugar mixture.
Roll up jelly-roll style, starting with a long side; pinch seam to seal. Cut into 12 slices. Repeat with remaining dough, butter and sugar mixture. Place 8 slices in each pan, cut side down. Cover with kitchen towels; let rise until doubled, about 30 minutes. Preheat oven to 350°.
Bake 30-35 minutes or until golden brown. Immediately invert onto serving plates. Serve warm.