Cake:

1 envelope active dry yeast
1/4 cup sugar
1/4 cup very warm water
1/4 cup milk
1/4 cup (1/2 stick) butter
3/4 teaspoon salt
2 eggs, beaten
2-1/2 to 3 cups unsifted all-purpose flour

Filling:

1/4 cup milk
1 pkg (6 oz.) semisweet chocolate pieces
1/2 teaspoon ground cinnamon
2 tablespoons butter
1/2 cup coarsely chopped walnuts
1 teaspoon water

Preheat oven to 350 deg.

Sprinkle yeast and 1/2 teaspoon of the sugar over very warm water in a 1-cup measure. (Very warm water should feel comfortably warm when dropped on wrist.) Stir to dissolve. Let stand 10 minutes until bubbly.

Heat milk, butter, remaining sugar and salt in a small saucepan just until butter is melted. Pour into large bowl. Cool to lukewarm.

Add eggs and yeast mixture to cooled milk mixture; stir until blended. Add 1-1/2 cups of the flour; beat well for 2 minutes. Stir in just enough of the remaining flour to make a soft dough.

Turn out onto lightly floured surface. Knead until smooth and elastic, about 8 minutes. Place dough in large greased bowl, turning to bring greased side up. Cover; let rise in a warm place, away from drafts, 2 hours, or until doubled in size.

While dough is rising, make filling. Heat milk, chocolate, cinnamon, and butter in small saucepan until butter melts; stir until smooth. Remove from heat. Reserve 1/4 cup of chocolate filling for topping. Let filling cool. Grease a 10x4" angel cake tube pan.

When dough is doubled, punch down; let rest 5 minutes. Roll to a 20 x 10" rectangle on a lightly floured surface. Spread filling to within 1/2" of edges on long sides and clear to the ends on the short sides. Sprinkle with nuts; roll up jelly-roll fashion, from long side. Pinch seam edge; place seam-side down in prepared pan. Pinch ends to seal well. Cover and let rise in warm place until doubled in volume, about 1 hour.

Bake in a moderate oven (350 deg.) for 45 minutes or until cake sounds hollow when tapped. Loosen around edges with spatula. Turn out onto wire rack. (Chocolate filling will show through in places.)

Stir 1 teaspoon water into reserved chocolate; spoon over warm cake.