Gin & tonic has always been one of my favorite cocktails, even — ahem — before I officially turned 21.

We’ll keep that between you and me, of course.

Evocative of a walk through a spring meadow, it’s a sip that’s light, bright, and so refreshing that it’s nearly impossible to resist — even when you’re 20 3/4. Or, uh, something near that.

Now, South American chef Francis Mallmann has taken the classic up a notch by incorporating a bit of fire.

“Gin and Tonic with Burnt Lemon and Cucumber” is from his newest cookbook, “Green Fire” (Artisan), of which I received a review copy. It was written with co-writer Peter Kaminsky and collaborator Donna Gelb.

If you’ve ever watched any of the late-great Anthony Bourdain’s shows, you’re probably already familiar with Mallmann, who owns Siete Fuegos in Argentina, Patagonia Sur in Buenos Aires, El Garzon in Uruguay, 1884 Restaurante in Argentina, and Los Fuegos in Miami.

Usually, he’s shown cooking over an immense live-fire grill with enough adjustable racks and levers to make it resemble some sort of medieval rack.

While some of his previous books were especially challenging because few — if any — of us are equipped to grill quite like that, this one thankfully is not. In fact, the recipes offer options for cooking the dish indoors, too, such as on a cast-iron pan or griddle on the stovetop.

What also sets this book apart is that it eschews meat, and concentrates solely on recipes and techniques to cook fruit and vegetables instead. Take a taste of everything from “Charred Tomatoes with Garlic and Thyme,” “Artichokes Mimosa with Aioli,” and “Beet, Lentil, and Avocado Salad with Crunchy Rice,” to “Griddled Chickpea Salad” and “Roasted Strawberries with Ricotta and Mint.”

The next time you’re grilling, stick a slice of lemon and cucumber on the grill for about a minute, turning them over to char both sides. Or use a cast-iron pan on top of the stove like I did.

Let cool, then pour your favorite gin and tonic water into a glass with ice. Garnish with the charred lemon and cucumber. Even though it wasn’t listed in the ingredients, the photo in the book showed the cocktail with a fresh mint sprig, as well. It’s a nice touch, so I added that to the recipe below.

I also liked muddling the lemon and cucumber in the glass to bring out more of their smoky flavors, so I also added that to the directions.

You end up with a gin & tonic as exhilarating as always, but enlivened with the lemon, cucumber and mint, along with a subtle smokiness.

This is a gin & tonic that looks impressive in a glass. Nobody has to know, though, just how easy it is to whip up.

Gin and Tonic with Burnt Lemon and Cucumber

(Makes 1 drink)

1 slice lemon

1 slice cucumber

1 ounce gin

3 ounces tonic water

Fresh mint leaves, for garnish (optional)

Prepare a fire for medium heat and warm the plancha. If cooking indoors, heat a cast-iron skillet or griddle over medium heat.

Set the lemon and cucumber slices on the hot plancha or skillet for a minute or two until lightly charred but still juicy. Let cool.

Pour the gin and tonic over ice in a tall glass. Garnish with the burnt lemon and cucumber. Muddle both slightly, and serve.

Adapted from “Green Fire” by Francis Mallmann

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And: Tony Negroni

And: Duende’s Turmeric Tonic

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