Combine brown sugar and butter and beat until fluffy. Add vanilla and egg; beat well. Add flour, baking powder and salt; blend well. Place 1 cup of dough in sm. bowl; blend in melted chocolate and baking soda.
On 12x8 in. sheet of plastic wrap, press half of light dough to form 10x4 in. strip. Shape half of chocolate dough into roll 10 in. long; place on strip of light dough. Mold sides of light dough around chocolate dough; wrap in plastic wrap. Repeat with remaining dough. Refrigerate for 1 hr.
Preheat oven to 350 degrees. Cut dough into 1/8 to 1/4 in. slices. Place 2 slices, sides touching, on ungreased cooking sheets to resemble owl faces. Pinch the corner of each slice to form ears. Place chocolate chip in center of each slice for eyes; press whole cashew between slices for beak.
Bake for 8 - 10 min. or until edges are light golden brown.