Heat oven to 325°F. In large bowl, beat powdered sugar, butter and vanilla with electric mixer on medium speed until light and fluffy. On low speed, beat in flour, almonds and salt until well blended. Stir in 1/2 cup toffee bits.
Shape dough into 1-inch balls. Shape each ball into 2-inch-long log; bend into crescent shape. On ungreased cookie sheets, place crescents 1 inch apart.
Bake 13 to 15 minutes or until set and bottoms are golden brown. Immediately remove from cookie sheets to cooling racks. Cool completely, about 30 minutes.
In 1-cup microwavable measuring cup, microwave chocolate chips and shortening on High 30 seconds. Stir; continue microwaving, stirring every 10 seconds, until chocolate is melted and can be stirred smooth. Dip 1 end of each cookie halfway into melted chocolate, letting excess drip off. If desired, sprinkle additional toffee bits over chocolate. Place on waxed paper or cooking parchment paper until set.