Food.com, the Food Network and My Recipes provide recipes for limoncello martinis. Food and Wine also provides a recipe that adds basil sprigs to the mix.
Make a basic limoncello martini using lemons, vodka, water and sugar. First, peel the zest from the lemon, avoiding the white rind or pith. Combine the zest with 1 bottle of vodka, and allow the mixture to cure at room temperature for four days. Add 2 1/2 cups of sugar and 3 1/2 cups of water to a saucepan, and heat it over medium until the sugar dissolves into a syrup. Pour the mixture into the pitcher containing the vodka and lemon, and allow it to cure overnight. Strain out the lemon peels, and chill before serving.
To make limoncello martinis without the wait time, combine 8 tablespsoons of limoncello with 4 teaspoons of fresh lemon juice. Divide the mixture among glasses, and add lemon rind strips. Add chilled champagne, and serve.
Make a lemon and basil martini by boiling equal parts of water and sugar together to make a simple syrup. Put 1 ounce of the syrup and 3 basil leaves into a cocktail shaker. Add ice, 2 ounces of gin, 1/2 ounce of limoncello, 1/2 ounce of sweet white vermouth and 1/2 ounce of fresh lemon juice. Shake all the ingredients well, and serve with a basil sprig as a garnish.