I have a bottle of Vanilla Vodka in the cabinet and I was trying to find something to mix with it - voila!
Wedding Cake Martini
2 oz vanilla vodka
2 oz pineapple juice
2 oz sweet n sour
Shake vigorously over ice then strain into sugar rimmed martini glass.
I have also seen another version - just swap out the sweet n sour for Amaretto (Disaronno).