Quick, make these before the last watermelon rolls out of sight to make way for pumpkins and corn sheaves at your grocery store. (It’s happening now. I saw chocolate turkeys on the shelf last Saturday, and that’s just wrong. What is the rush?!)

It’s hot on my backyard deck – 116°F. this very minute, according to an old thermometer that’s been baking in the sun all day. Even discounting a few digits for thermometer decrepitude, it’s hot.  A tropical cocktail in this climate is not stretching the season, even if the calendar says September. It’s still summer in Arkansas.

I am fortunate to have friends who don’t mind being guinea pigs for new recipes. They are also good-natured about being pressed into cooking duty when I need another pair of hands (or three) to get all the elements of dinner on the table. My friend J was willing to whisk bearnaise sauce Saturday (a curious geometric motion that I’ve never seen before), but he was happiest when sipping these.

Watermelon Margaritas, adapted from Cocktails for a Crowd, by Kara Newman, © 2013 by Kara Newman, published by Chronicle Books of San Francisco, California. The idea behind this book is genius. Most occasions for sharing cocktails require making a multitude of drinks, yet most cocktail recipes are scaled for single servings. Result: more work for the host, more wait for the guests. Ms. Newman has devised large-batch recipes for delicious cocktails that will please guests and hosts alike.

3 cups chopped, seedless watermelon (I found the “personal size” watermelon yields the perfect amount of fruit for this recipe, with a few pieces leftover for garnishes and snacking. Slice the fruit into wedges, then remove the rind from most of it and cut into smaller pieces for processing. Save a few pieces with rind attached to cut into triangles for garnishing the drinks.)

12 ounces silver tequila, chilled

6 ounces Grand Marnier, chilled

6 ounces freshly squeezed lime juice, chilled

Simple syrup (This is useful for sweetening any kind of drink, from cocktails to iced tea. Combine 1 cup water and 1 cup granulated sugar in a small saucepan. Bring to a boil over medium-high heat, then reduce heat to low and simmer for about 10 minutes. Remove saucepan from heat, and let syrup cool to room temperature. Pour into a bottle with lid, and store in the refrigerator.)

4 cups ice cubes

Put the chopped fruit, minus the rind, into a food processor fitted with a knife blade. Process until smooth. Pour the liquid through a strainer into a large measuring cup to total about 2 cups of juice. Combine the watermelon juice, tequila, Grand Marnier, and lime juice in a pretty pitcher that will hold about 10 cups of liquid. Stir well. Taste for sweetness, adding simple syrup if necessary. Stir again, then refrigerate.

Just before serving, stir 4 cups of ice into the pitcher. Pour the margaritas into ice-filled tumblers, and garnish each with a jaunty slice of melon. Cookbook author Newman recommends wetting the rims of the glasses with a slice of lime, then dipping the rims into a mix of crushed pink peppercorns and sea salt. I did that but can’t recommend it. The drinks are pretty and delicious as is.