1. Heat oven to 325 degrees . Coat a baking sheet with vegetable spray or line baking sheet with parchment paper.
2. In a large bowl, beat egg whites until foamy. Gradually add sugar and continue to beat until glossy stiff peaks form, about 4 minutes.
3. Add cooled chocolate, pecans and vanilla, mixing until incorporated.
4. Drop tablespoonfuls of mixture onto prepared baking sheet, 2 inches apart.
5. Bake at 325 degrees for 12 minutes, until set. Cool on baking sheet 2 minutes. Transfer cookies to a wire rack to cool completely.