1. Heat oven to 350 degrees . In a bowl, stir together flour, finely ground pistachios and salt. In another bowl, beat butter and sugar for 2 minutes, until fluffy. Beat in egg. Pour in dry mixture and beat until just combined.
2. Shape level tablespoonfuls of dough into 21/2-inch logs and bend into crescents. Place on a baking sheet 2 inches apart. Bake at 350 degrees for 14 to 16 minutes, until lightly browned. Remove to a wire rack to cool completely.
3. Melt chocolate per package directions. Dip crescents halfway into chocolate, allowing excess to drip off. Sprinkle with chopped pistachios. Place on parchment paper to dry.