Chocolate rugelach are traditional Jewish cookies that have gone mainstream and luckily are easy to make. The dough is made with butter and cream cheese, a tradition stemming from the Middle East, which became popular in central Europe. Jewish immigrants introduced rugelach to the United States. The word "rugelach" is Yiddish and comes from the Polish "rogal," meaning "horn." This refers to the cookie's crescent shape. The filling is usually either chocolate or jam.
Cut the butter and cream cheese into cubes. Pulse the flour, butter and cream cheese in a food processor until it forms a soft, crumbly dough. Place the dough in a bowl, cover with plastic wrap, and refrigerate for at least one hour or overnight.
Grate or finely chop 8 ounces bitter chocolate. Combine with 1/4-cup sugar and 1/2 teaspoon cinnamon. If you like, add 1/2-cup finely chopped nuts, such as walnuts or almonds. (For a variation, substitute 1/2-cup roughly chopped dried cherries for the nuts.)
Divide the dough into four equal balls. Keep the three balls you aren't working with at the moment in the refrigerator. It's important to keep the dough well chilled so it's easier to work with.
On a lightly floured surface, roll out one dough ball into a circle, that is about about 1/8-inch thick. Sprinkle with one quarter of the chocolate mixture. Cut the circle into twelve wedges. Roll each wedge up, starting from the wide end, into a crescent shape. Repeat the process with the rest of the dough and filling.
Place the rugelach on a greased cookie sheet. Lightly beat an egg and brush the tops, then sprinkle with the remaining 1/4-cup sugar. Bake at 350 for 25 minutes.
Makes about 50 chocolate rugelach.