Visuals count, especially when appetites wilted by summer heat need a pick-me-up. The look of this eggplant and tomato casserole is just the thing, the glossy purple of the eggplant offset by the red stripes of the sliced tomatoes that have been wedged gently into the eggplant before baking.

I’ve never forgotten how impressed I was the first time I saw this tian d’aubergines in 1999 in Chester, Conn. Monique Hanson, former owner of a home-based cooking school, was making the dish for a lunch party the next day; I was writing a series about local cooks for the Hartford Courant.

Hanson, now retired and still living in that small Connecticut River town, continues to make this dish, often pairing it with leg of lamb seasoned with herbes de Provence. The dish can be served hot, cold or room temperature. Now, she likes it cold.

“In the summer, it’s always nice to have something cold when it’s hot outside,” Hanson said recently by phone.

Along with its appearance, it also will be hard to forget how good this dish tastes, particularly if you are using just-harvested eggplant, ripe tomatoes and fresh-picked thyme from the farmers market or your garden.

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TIAN D’AUBERGINES

Prep: 30 minutes

Cook: 2 hours

Makes: 6 servings

Use a baking dish that can hold the eggplant snugly. I’d probably do the baking the night before or early in the morning before the heat of the day takes hold. Improvise with aluminum foil if your baking dish lacks a lid.

2 onions, peeled, thinly sliced

1 tablespoon fresh thyme, minced

2 or 3 medium eggplants

4 to 5 tomatoes, sliced

2 tablespoons balsamic vinegar

1 tablespoon Dijon mustard

6 tablespoons olive oil

Salt and pepper to taste

1. Heat oven to 350 degrees. Lightly oil a gratin dish or casserole; spread the sliced onions on the bottom. Sprinkle the thyme over the onions.

2. Slice the unpeeled eggplants at roughly 1/4-inch intervals, taking care not to cut all the way through; you want the eggplant slices to remain attached to each other.

3. Insert a tomato slice into each cut of the eggplants. Slicing the tomatoes on a slant will permit a better fit in layering them into the eggplant. Make sure the top of each tomato slice is level with the top of the eggplant for a nicer presentation.

4. Arrange the eggplants layered with tomatoes on top of the sliced onions.

5. In a small bowl, make a vinaigrette: Mix the vinegar and mustard together; while whisking, slowly add the oil to ensure the mix emulsifies and thickens. Drizzle the vinaigrette over the eggplant. Season to taste with salt and pepper.

6. Cook, uncovered, 1 hour. Cover; cook until the eggplant is cooked through and soft, 1 hour. Serve hot, cold or at room temperature.