A herd of black Iberian pigs snuffed through dry grass among the oak trees, kicking up dust as they searched for fallen acorns in southwestern Spain. The ham from their cured legs was the reason I found myself in this nature preserve about an hour from Seville, where the pigs stuff themselves every autumn during the last months of their lives. 

I’d come for a yearly ritual called the engorde, or fattening, which infuses the pork with the acorns’ nutty flavor and makes it some of the most expensive meat on the planet.

The sliced jamón ibérico, naturally, was delicious. But at dinner that night with the farmer, Paco Martín, who raises the purebred pigs, I was surprised that the other star on the table was something I’d eaten countless times before: tortilla española. 

In Spain, tortillas are similar to frittatas, made by combining whipped eggs with sautéed potatoes and onions. The mixture cooks in a skillet with a fair amount of oil. It’s a common breakfast at home but also a staple of tapas menus, normally reheated by the slice and served with pan con tomate, crusty bread that’s been rubbed with fresh tomato and drizzled with olive oil. But this tortilla carried a deeper, sweeter richness.

When I arrived for dinner at Martín’s one-story stone farmhouse, spread out on a plaid tablecloth was a simple array: fruity olives, crackers, slices of Manchego cheese, plates of cured ham and the tortilla. I found myself going back for two extra helpings of the tortilla, which was savory, herbaceous and sweet, and somehow one of the most satisfying egg dishes I’d ever had. 

It turns out the secret was simple. Most cooks only briefly cook the onions and potatoes in a generous amount of oil before adding the eggs. But Martín’s wife, Maria, also adds a fistful of chopped parsley and chunks of white eggplant—a rare addition to a tortilla. More importantly, she lets the vegetables linger in the pan. Cooking them for about five minutes longer than normal was enough to caramelize them slightly, adding sweet dimension to an otherwise routinely savory dish.

Maria’s tortilla was easy to recreate back at Milk Street, but it was necessary to make some changes to the traditional cooking method. 

First, we had to find the right kind of eggplant. Chinese or Japanese varieties produce the best results, but Italian or globe eggplants also work if their tougher skin is removed. We whisked eggs and added chopped parsley, salt and pepper, then set them aside while we sautéed the cubed eggplant along with onions and potatoes.

We initially cooked the vegetables over medium-low until they were well browned; that took 30 minutes—longer than we wanted. We found that covering the pan and using medium-­high heat significantly sped things up, to just 10 minutes.

While a traditional Spanish tortilla is cooked entirely on the stovetop—coaxed out of the pan halfway through cooking, inverted onto a plate and slid back into the pan—we opted out of the culinary gymnastics. 

We let the egg mixture set on the stovetop, then put the pan in the oven to finish cooking. The result was a simple and homey meal that still delivered the deep and distinct flavors we loved in Spain.