Preheat oven to 325 degrees F. Line 2 baking sheets with parchment paper or nonstick baking mats.

Thoroughly stir together confectioners' sugar, cocoa, flour and salt in a large bowl. Beat in egg whites, one at a time, with an electric mixer on low speed. Add vanilla paste (or extract) and beat for 1 1/2 minutes on high speed, scraping down the sides of the bowl several times. Fold in pecans, chocolate and cocoa nibs until evenly incorporated.

Spoon the dough by heaping tablespoonfuls onto the prepared baking sheets, about 2 inches apart.

Bake the cookies, in batches, in the center of the oven, until dry and glossy on the surface but soft in the centers when pressed, 15 to 17 minutes. Let cool on the pan for 5 to 10 minutes. Carefully transfer the cookies, on the paper or mats, to a wire rack to cool completely.

Ingredient notes: One tablespoon of vanilla paste is equivalent to 1 whole bean. Find it in specialty baking shops or online at thespicehouse.com.

You can find cocoa nibs (bits of roasted and hulled cocoa beans) at large grocery stores, gourmet retailers or online at chocosphere.com.

MAKE AHEAD TIP: Store in an airtight container at room temperature for up to 3 days or freeze for up to 1 month.