1. Preheat oven to 325°. In a small bowl, cream butter and confectioners' sugar until light and fluffy. Beat in vanilla. Combine flour, hazelnuts, and salt; gradually add to creamed mixture and mix well. Shape 1 tablespoon of dough into a ball; pinch the dough to form a face. Repeat. Place 2 in. apart on a greased baking sheet.
2. Bake 12-15 minutes or until lightly browned. Let stand 5 minutes before removing to a wire rack to cool completely.
3. In a microwave, melt chocolate; stir until smooth. Holding a hedgehog cookie by the nose, spoon chocolate over the back (leave the face uncovered). Allow excess to drip off. Place on waxed paper; immediately sprinkle crushed toffee onto the wet chocolate to look like hedgehog spikes.
4. With a toothpick dipped in chocolate, make two eyes and a dot on the nose. Let stand until set. Store in an airtight container.