Heat oven to 400°F. Grease 12 (2 3/4x1 1/4-inch) nonstick muffin cups. In medium microwave-safe bowl, combine chocolate chips and butter. Microwave on High for 45 to 60 seconds or until melted, stirring every 15 seconds until smooth. Cool 5 minutes.
In large bowl, combine eggs and egg yolks; beat with electric mixer at high speed for 4 to 6 minutes or until foamy and doubled in size. Reserve chocolate syrup packet from brownie mix. Gradually add brownie mix to egg mixture, beating until well blended. Fold in melted chocolate chip mixture and liqueur. Divide batter evenly into greased muffin cups. (Cups will be full.)
Bake at 400°F. for 10 to 14 minutes or until edges are set. DO NOT OVERBAKE. Centers will be soft. Cool 2 minutes.
While cakes are cooling, drizzle chocolate syrup from packet onto each individual serving plate. Run knife around edge of each cake to loosen. Invert warm cake over chocolate on each plate. Garnish each serving with strawberry and mint sprig. Serve with ice cream.