Dissolve yeast and 2 teaspoons sugar in milk; set aside. Combine flour, salt and remaining sugar. Cut in butter until mixture resembles coarse crumbs. Beat the egg yolks into the cream; add to the flour mixture along with the yeast mixture. Blend well and form into a ball. Place dough in a greased bowl; cover and refrigerate overnight.
Punch dough down; place on a lightly floured surface and divide into six balls. Using hands, roll each ball into a 24-in. rope. On a greased baking sheet, twist two ropes together, then shape into a 6- to 8-in. ring. Pinch ends together and sprinkle with nuts. Repeat with remaining two rings. Cover and let rise until almost doubled, about 30 minutes.
Bake at 350° for 25 minutes. Bake at 350° for about 25 minutes or until golden brown. Place on wire racks. Combine icing ingredients; drizzle over warm rings.