Years ago, I went to a summer potluck, where the first dish to be demolished was a friend’s homegrown tomatoes, simply sliced, arranged on a pretty platter, and dressed with olive oil, and sea salt.

Not that the other dishes weren’t fabulous. It was just that tomatoes like that, ripened on the vine to let their deep, natural sweetness, tartness and mouthwatering savoriness develop to their fullest are absolutely impossible to resist.

When summer provides tomatoes that good, you don’t have to do much to them. That’s why “Tonnato with Tomatoes” is such a winning recipe.

It’s little more than an assortment of sliced tomatoes drizzled with the creamy Italian sauce of tuna, anchovies, capers, and lemon juice that’s traditionally spooned over cold slices of veal. It’s like the taste of a tuna salad sandwich with slices of fresh tomatoes inside — but turned on its bread with the tomatoes the star and the tuna a supporting yet major player.

This super easy recipe is from “Big Night” (Union Square & Co.), of which I received a review copy.

It’s by Katherine Lewin, who went from a career as a copywriter at J.Crew to a food writer and editor at The Infatuation to opening two Big Night gourmet stores in New York City.

Lewin’s philosophy is that any night can be a Big Night. Whether you’re having company over or just cooking for your own household, any meal can be made to feel more special — without fuss or anxiety. Even store-bought or takeout feels like an occasion if it’s put into a proper bowl or serving platter. Entertaining need not be all about the fancy or complicated. After all, even the most basic of foods has a way of tasting better when it’s served in a nurturing way.

To that end, you’ll find accessible recipes made for satisfying such as “Ricotta Toasts For Every Mood,” “Bulgogi-Ish Lettuce Wraps,” “Amatraciana For A Crowd,” and “Stonefruit Dreamsicle Pie,” plus a complete menu from cocktails to cheese plate to main-course turkey and dessert for “The Best Friendsgiving.”

For “Tonnato with Tomatoes,” choose your favorite, best tasting heirloom beefsteaks and cherry tomatoes. Slice them, and arrange on a serving platter.

In a blender of food processor, whiz together lemon zest, lemon juice, oil-packed tuna, oil-packed anchovies, garlic, mayo, Dijon mustard, and capers. Drizzle in a little of the oil from the tuna and anchovy tins, and blend.

Dollop spoonfuls of this rich sauce over the tomatoes. Add a pinch of sea salt and chili flakes, if you like. It’s as simple as that.

The tonnato is a force — sharp, briny, lemony and garlicky. It is nothing short of magical with fresh tomatoes.

Set the platter on the table. And don’t be surprised if its contents are gone in a flash.

Tonnato with Tomatoes

(Serves 8 to 12)

2 pounds mixed heirloom tomatoes, thinly sliced

1 1/2 pounds small tomatoes, such as Campari or cherry tomatoes, halved

Kosher salt

3 to 4 lemons

1 garlic clove, peeled

1 (5- to 7-ounce) tin or jar oil-packed tuna

4 oil-packed anchovy fillets

1/2 cup mayonnaise, plus more as needed

2 tablespoons Dijon mustard

2 tablespoons brined capers, drained

Freshly ground black pepper

Extra-virgin olive oil, for serving

Flaky sea salt, for serving

Chile flakes, for serving (optional)

Line a plate with towels or a kitchen towel and arrange the tomatoes on top. Season them all over with salt and set aside to drain.

Meanwhile, zest and juice the lemons. You should have 2 tablespoons of zest and at least 1/4 cup of juice. Transfer the zest and 3 tablespoons of the juice to a blender or food processor, then grate the garlic into the blender. Drain the tuna and anchovies, but don’t toss the oil. Add the tuna, anchovies, mayonnaise, mustard, capers, and a few good grinds of pepper to the blender. Blend the mixture on medium speed until very smooth, a minute or less. With the blender running, slowly drizzle in 2 tablespoons of the reserved tuna or anchovy oil. Taste the tonnato and season with more lemon juice and salt as needed.

Arrange the tomatoes on a serving platter and pour over as much tonnato as you’d like (I like a lot of tonnato). Drizzle with olive oil and sprinkle with a bit of flaky salt, more pepper, and chile flakes (if using). Serve immediately.

From “Big Night” by Katherine Lewin

More Tonnato To Savor: Charred Broccoli with Tonnato, Pecorino, Lemon, and Chiles