Heat oven to 350°F. Line two 9-inch round pans with foil; lightly spray foil with nonstick cooking spray.
In large bowl, combine brownie mix, chocolate syrup from packet, water, oil and egg. Beat 50 strokes with spoon until all dry mix is moistened. Divide batter evenly into sprayed foil-lined pans; spread evenly.
Bake at 350°F. for 18 to 22 minutes or until toothpick inserted in center comes out clean. Cool 20 minutes. Remove brownies from pans by lifting foil. Cool 1 hour or until completely cooled. Remove foil.
In small bowl, combine whipped topping and liqueur; fold gently to mix.
To assemble dessert, place one brownie round, top side down, on serving plate. Spread with half of filling mixture. Arrange half of sliced strawberries in thin layer over filling. Top with second brownie round, top side up. Spread with remaining filling mixture. Arrange remaining strawberry slices over top. Store in refrigerator.