1Heat oven to 350°F (325°F for dark or nonstick pan). Place paper baking cup in each of 12 regular-size muffin cups. Make cupcake mix as directed on box, using water, oil and whole eggs. Fill muffin cups with batter and filling as directed. Bake 24 to 29 minutes or until surface of cupcakes appears dry. Cool 20 minutes; remove cupcakes from pan to cooling rack. Cool completely.
2In 2-quart saucepan, heat sugar and 1/3 cup water to boiling over medium heat, without stirring. Boil about 3 minutes, without stirring, to 238°F on candy thermometer or until small amount of mixture dropped into cup of very cold water forms a soft ball that flattens when removed from water; remove from heat. In large bowl, beat egg whites, cream of tartar and vanilla with electric mixer on high speed until soft peaks form. Gradually add sugar syrup, beating until stiff peaks form, about 5 minutes.
3Spoon frosting into decorating bag fitted with #6 large round tip. Pipe frosting onto cupcakes. Spoon melted chocolate over frosting. Sprinkle with pecans.