Step 1

Two days in advance (to allow time to freeze; longer is fine) combine the first 5 ingredients in a very large, plastic (freezable) container or distribute evenly among two containers. (I use a large, plastic pretzel tub.) Stir well, cover, and freeze.

Step 2

When ready to serve, allow the frozen mixture to sit at room temperature for a few minutes, and then scrape with a fork, and transfer to glasses for serving. The mixture will become slushy-like as it sits. Unused portions may be refrozen and are also delicious on the rocks when fully melted.

Step 3

To serve with salted rims if desired: wet rims of glasses with lime juice, coat rims with salt, and garnish with a lime slice.