Directions

1. Cream butter and sugar together until light, about 5 minutes. Sift flour with cocoa.
2. Beat into butter mixture. Divide dough into four square pieces. Wrap and refrigerate for at least one hour.
3. Roll out one piece of dough on a lightly floured surface and cut into 12 squares of about 2 in (5cm) each. Repeat with remaining pieces of dough. Arrange cookies on baking sheets lined with parchment paper. (Cookies will not spread too much, if at all, as they bake.)
4. Bake in a preheated 275°F (140°C) oven for 20 to 25 minutes. Remove from oven then, after 15 minutes, transfer to a cooling rack.
5. Melt chocolate in a 2-cup (500-mL) measuring cup. Dip cookies in the chocolate on the diagonal so that half are covered from one corner to another in white chocolate. Allow excess white chocolate to drain off and arrange cookies on rack. Refrigerate until set.