My favorite:

1 oz lemon flavored vodka
1 oz Limoncello liqueur
1 oz sweet and sour
Lemon juice and superfine sugar to taste

Mix the vodka, Limocello, sugar, sweet & sour and lemon juice in a cocktail shaker half-filled with ice; shake well. Pour strained liquor into sugar-rimmed martini glass and garnish with a twisted peel of lemon.

Yum yum yum!