|All purpose flour||2 Cup (32 tbs)|
|Baking powder||1 Teaspoon|
|Butter/Margarine||9 Tablespoon, softened (1 Stick)|
|Sugar||1 Cup (16 tbs)|
|Vanilla extract||1 Teaspoon|
|Semi sweet chocolate||1 Ounce (1 Square)|
|Unsweetened cocoa||3 Tablespoon|
1. In small bowl, combine flour, baking powder, and salt. In medium bowl, with mixer at medium speed, beat 1/2 cup butter and sugar until creamy. Reduce speed to low; beat in egg and vanilla until blended. Beat in flour mixture just until combined, occasionally scraping bowl with rubber spatula. Transfer half of dough to sheet of waxed paper.
2. In 2-quart saucepan, melt chocolate and remaining 1 tablespoon butter over very low heat. Stir in cocoa until combined. Add chocolate mixture to dough in bowl, stirring until blended.
3. Roll chocolate dough between two sheets of waxed paper into 12" by 10" rectangle. Repeat with vanilla dough. Remove top sheets of waxed paper from chocolate and vanilla doughs. Using waxed paper, turn vanilla dough over onto chocolate dough. Peel off top sheet of waxed paper. Using bottom piece of waxed paper to help, roll up doughs together jelly-roll fashion. Wrap dough in plastic wrap and refrigerate until very firm, at least 4 hours or up to overnight.
4. Preheat the oven to 375°F. Grease two large cookie sheets.
5. Cut dough crosswise into 1/4-inch-thick slices. Place the slices, 1/2 inch apart, on the prepared cookie sheets.
6. Bake just until golden, 10 to 12 minutes, rotating cookie sheets between upper and lower oven racks halfway through baking. Cool on cookie sheets on wire racks 5 minutes. With wide spatula, transfer to wire racks to cool completely.