Mach 6

1 oz white creme de cacao
1 oz sweet sherry
1/2 oz white rum
2 oz pineapple juice
1 tbsp pineapple
1 tsp grenadine syrup

Blend ingredients in a highball glass until smooth. Add three-quarters of a glassful of crushed ice and blend again briefly. Garnish with a pineapple chunk and a cherry, and serve with straws.