ALMOND CRUST: In medium bowl, stir together graham cracker crumbs, almonds and sugar. Stir in butter; blend well. Press mixture onto bottom and up side of 8 inch spring-form pan.
CHEESECAKE: Heat oven to 325°F. In top of double boiler over hot, not boiling, water, melt chocolate bar pieces; set aside.
In large mixer bowl, beat cream cheese until light and fluffy. Stir together sugar, cocoa and salt; blend into cream cheese mixture. Beat in eggs and vanilla. Add reserved melted chocolate; beat just until blended (do not over beat). Pour batter into almond crust.
Bake 35-40 minutes or until set. Remove from oven to wire rack. With knife, loosen cake from side of pan; cool to room temperature.
SOUR CREAM TOPPING: In small bowl, stir together sour cream, sugar and vanilla. Spread over cooled cheesecake. Refrigerate several hours or overnight; remove side of pan. Cover; refrigerate leftover cheesecake.