1Heat oven to 450°F. Grease bottoms and sides of six (6-oz) custard cups with shortening; dust with cocoa. In 2-quart saucepan, melt chocolate and butter over low heat, stirring frequently. Cool slightly.
2In large bowl, beat whole eggs and egg yolks with wire whisk or eggbeater until well blended. Beat in 1 1/2 cups powdered sugar. Beat in melted chocolate mixture and flour. Divide batter evenly among custard cups. Place cups on cookie sheet with sides.
3Bake 12 to 14 minutes or until sides are set and centers are still soft (tops will be puffed and cracked). Let stand 3 minutes. Run small knife or metal spatula along sides of cakes to loosen. Immediately place heatproof serving plate upside down over each cup; turn plate and cup over. Remove cup. Sprinkle with additional powdered sugar. Garnish with kumquats. Serve warm.