Preheat oven to 325°.

In a large mixing bowl beat butter with an electric mixer on medium to high speed for 30 seconds.

Add the 2/3 cup powdered sugar, espresso powder, vanilla, and cinnamon.

Beat until combined, scraping sides of bowl occasionally.

Beat in as much of the flour as you can with the mixer.

Stir in any remaining flour and the chocolate; if necessary, knead dough slightly to blend.

Shape dough into 1-inch balls.

Place balls 2 inches apart on an ungreased cookie sheet.

Press to flatten slightly.

Bake 12 minutes or until cookie edges are set and bottoms are lightly browned.

Transfer to a wire rack and let cool.

Sift additional powdered sugar and/or cocoa powder over cooled cookies.

Store-layer cookies between waxed paper in an airtight storage container; cover.

Store at room temperature for up to 3 days or freeze for up to 3 months.