Pour thawed limeade concentrate into blender. Add tequila. Cointreau, lime juice and 2 lime slices. Whirl ingredients briefly;pour half into a shallow container and freeze. Add a few handfuls of ice to the mixture remaining in the blender and whirl till slushy. Pour immediately into chilled margarita glasses with salted rims and garnish with lime slices. Repeat with second batch.

concentrates, such as strawberry-guava or orange-passion fruit, for limeade. Or, use fresh seasonal fruits;freezing them first produces an icy drink without diluting the flavor.

Peeled, sliced fresh mangoes, peaches, pineapple and whole strawberries freeze well. So do whole prickly pear, kiwi and bananas. Use Mexican limones (key limes) whenever possible. Keep tequila in freezer for icier drinks.