Searching for an easy way to improve the flavor and texture of grilled vegetables, we realized we were overlooking the most obvious ingredient—the flames themselves.

Grilling vegetables isn't new, but in Spain’s Catalonia region, they are scorched, adding the deep flavors of char and smoke. Calçotada, for example, involves burning the exterior of young wild onions (calçots). The burnt outer layer then is peeled off and the onion is dipped in a romesco sauce and eaten in one big, sloppy bite.

One dish in particular, escalivada, gave us the bold flavor—and simplicity—we were looking for. This common side dish—a mix of fire-roasted eggplant, red pepper and onion (sometimes tomato, too)—gets its name from the Catalan word escalivar, which means to cook in the ashes.

The vegetables are charred on the coals of a wood fire, then the skins are peeled off. The vegetables are sliced and arranged on a platter with little more than a heavy glug of olive oil, a sprinkling of salt and a splash of tangy sherry vinegar. Sometimes, it gets a garnish of chopped herbs, such as parsley or chives.

At Milk Street, we liked this meat-like treatment of vegetables. But we needed to make some adjustments to streamline the process and add texture, starting with the cooking. Since most Americans grill over gas or briquettes, setting the vegetables directly only hot coals wasn't an option. Instead, we prepped the grill for both direct high heat and indirect low heat. This gave us the ability to char the vegetables first, then let them finish and become tender inside over lower heat, a technique we often use with steak.

Though globe eggplants are more traditional, we favored Japanese eggplants for their thinner skin; no need to peel them. As the grill heated, we tossed halved eggplants, a whole bell pepper and two varities of onions—red and scallions, which produced different textures and flavors—in olive oil, paprika and salt and pepper.

After grilling, the vegetables are chopped into bite-size pieces. But despite the char, the vegetables were uniformly tender. And while we liked the smokiness, it overwhelmed the other flavors. The solution was to mix the cooked vegetables with fresh halved cherry tomatoes, adding a sweet acidity and firm texture. The red onion, though softened, also added a bit of crunch.

A final shot of sherry vinegar brightened and balanced the smoky dish. And just half a teaspoon of honey was enough to complement the caramelized sugars in the vegetables and helped balance the hot paprika.