Preheat oven to 350 degrees.
Line 24 muffin cups with paper bake cups. Set aside.
In small saucepan, melt butter and chocolate over low heat.
Remove from heat and transfer to medium bowl.
Add eggs, sugar, vanilla, and salt.
Beat lightly with a wooden spoon just until combined.
Stir in flour and pecans.
Spoon a rounded tablespoonful of batter into muffin cups.
Bake about 20 minutes or until toothpick inserted into center comes out clean.
Cool on wire rack for about 5 minutes and then remove from tins.
Cool completely and sprinkle with powdered sugar.