In large mixing bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Add sour cream and egg yolk. Beat until combined. (dough will be sticky) Divide dough into fourths. Cover and chill for at least 1 hour or until dough is easy to handle.
for filling: In a small bowl, combine sugar, chocolate pieces and cinna mon; Set aside ( or if desired make Apricot-Walnut Filling).
On lightly floured surface, roll one-fourth of the dough into na 10-inch circle. Spread 1/4 of the filling over the circle. Cut the doughinto 12 wedges. Roll up each wedge, starting at wide end. Repeat with remainin g dough and filling.
Place cookies, tip side down, about 2 inches apart on foil-lined cookie sheets. Bake in a 350 degree oven for 20 minutes or until golden brown. transfer to wire racks to cool. If you like, sprinkle with powdered sugar. makes 48 cookies.
Apricot -Walnut filling: In a small saucepan, combine i cup finely snipped dried apricots or finely snipped dried cherries, 1/4 cup sugar and 1/4 cup water. Bring to boiling. Reduce heat and simmer, uncovered, for 5 minutes or until thickened, stirring occasionally. Remove from heat; coll. Stir in 1/2 cup finely chopped walnuts.
Store in an airtight contasiner at room temperature for up to 3 days, or freeze container for up to 3 months.