Preheat oven to 375 °F. In a bowl, cream butter with sugar.
Beat in vanilla , coconut extract, the whole egg and egg yolk.
In another bowl, sift together flour, baking powder, baking soda and salt.
Stir flour mixture into butter mixture. Stir in coconut. Chill and cover for 20 minutes or until firm.
With floured hands, shape dough into 2 and 1/2 inch logs. Put logs 3 inches apart on buttered baking sheets.
With a fork dipped in flour, flatten logs to 4 x 1 and 1/2 inch rectangles (marks from lines of fork should be lengthwise ).
Bake 10 - 12 minutes or until edges are golden. Let cool on baking sheets for 5 minutes.
Transfer cookies to wire racks to cool completely. Makes about 20 cookies.