From My Carolina Kitchen
If you like margaritas served in a glass with salt, rub the outside rims of six glasses with a cut lime and dip each glass lightly into a plate of kosher salt. Combine 1/2 cup freshly squeezed lime juice (5 limes), 2 tablespoons freshly squeezed lemon juice (1 lemon), 1 cup Triple Sec, and 3 cups ice in a blender and puree until completely blended. Add 1 cup white tequila and puree for 2 seconds more. Serve over ice. If you prefer frozen margaritas, halve each of the ingredients, double the ice, and blend in two batches. Serve with a cut lime. Serves 6.
From Ina Garten, The Barefoot Contessa Parties!