Cut a notch in a lime wedge, then run the lime around the rim of a glass. Dip the edge of the rim into a plate of the salt.
Place all ingredients in a cocktail shaker with 4 ice cubes and shake until cold.
Strain the margarita into the glass with the salted rim. Fill the glass with clear ice and serve.
Pitcher (8 servings): Place 1 1/2 cups Casamigos tequila, 1 cup Cointreau or Triple Sec, and ¾ cup lime juice in a pitcher. Add 3 handfuls ice and stir until cold.
Notes
*To convert to tablespoons, 1 ounce = 2 tablespoons