1. Heat oven to 325°F Combine 1/2 cup butter and cream cheese in small bowl. Beat at medium speed until smooth. Reduce speed to low; add all remaining shell ingredients. Beat until well mixed. (Mixture will be crumbly.).
2. Shape dough into 24 (1 1/4-inch) balls. Place one ball of dough into each ungreased mini muffin cup. Press dough evenly on bottom and up sides of muffin cup.
3. Melt baking chocolate and 3 tablespoons butter in small saucepan over low heat, stirring occasionally, until smooth (2 to 3 minutes). Remove from heat. Cool 5 minutes. Stir in all remaining filling ingredients.
4. Spoon filling into each shell. Bake for 26 to 28 minutes or until filling is set. Cool in pans 5 minutes. Carefully remove tartlets from pan. Cool completely on cooling racks over waxed paper.
5. Melt white baking bar and shortening in 1-quart saucepan over low heat, stirring occasionally, until smooth (2 to 4 minutes). Drizzle glaze over tartlets.