With Spanish cooking so much in the spotlight, it's no surprise that romesco, one of the cuisine's classic sauces, is reaching a wider audience.
Chefs in the United States are discovering its allure, and so should home cooks, especially in the summer to serve alongside whatever has been sizzling on the grill.
Romesco, a rustic, ruddy-hued, all-purpose sauce from Catalonia, is served with fish, poultry, meats and vegetables, and in stews. In that northeastern part of Spain, eating the seasonal grilled spring onions called calcots without romesco for dipping is unthinkable.
There is no standard recipe or even ingredient list for romesco. It invariably includes ripe tomatoes -- we did say summer? -- garlic, olive oil, almonds or hazelnuts, bread, and mild chiles, but the proportions can vary. It is not particularly spicy, unless you want it to be. The nuts and bread thicken it and give it texture.
David Sole i Torne, the chef and owner of Barquet, an elegant seafood restaurant in Tarragona, is a romesco expert.
''Each person makes romesco differently," he said. "And each insists that his is the authentic one."
The sauce contributes savory richness to many dishes, and not just Spanish ones.
At Boulud Sud near Lincoln Center in New York, the chef Aaron Chambers spoons it alongside portions of daurade, a Mediterranean fish.
''The sauce is also great as a dip for crudites, and you can use it to thicken soups," he said.
Luis Bollo, the chef and an owner of Salinas in New York, uses it to "punch up" a kind of Majorcan ratatouille served with red snapper. He likes it with lamb and to fold into rice and noodle dishes.
On the lunch menu at the Boqueria restaurants in New York, a lashing of romesco seasons a grilled chicken sandwich. The restaurants' executive chef, Marc Vidal, also likes it in a dressing for bitter greens like escarole or frisee, and in countless other dishes. In California, at Zuzu in Napa, it garnishes roasted potatoes and onions. And Gringo Jack's, a restaurant in Manchester, Vt., bottles and sells its romesco pasta sauce.
In the summer, think of slathering it on a burger or using it as a dip for fries or to replace butter on corn on the cob, as my granddaughters did when I tested the recipe. It is as versatile as mayonnaise, with even more personality, and keeps for weeks in the refrigerator.
But like professionals, the amateur cook should plan to make it, not buy it. There is no supermarket gold standard, as there is for mayonnaise. Romesco sold in small jars in Spain, or imported and sold here, is less vibrant than anything you can make at home.
Some cooks and chefs add wine, onions, roasted peppers like piquillos or red bell peppers, vinegar and Spanish paprika or cayenne. The ingredients are always cooked before being blended. Most chefs grill and roast them. Sole i Torne prefers frying, which for home cooks is an easier method than roasting batches of each ingredient.
Either way, it's a typical Mediterranean mixture, originally pounded in a mortar, like Italian pesto, and French rouille and tapenade. Near Tarragona, Victor Gilgado Martos, a local chef, demonstrated making romesco using a mortar in a farmhouse kitchen while the calcots were grilling outdoors. But halfway through, he picked up a hand blender. So it goes.
Traditionally, fishermen made it to eat with seafood. But when? Some say its origins are Roman, from the time that Tarragona was a provincial capital of the empire. Others credit the Moors. Sole i Torne said that "rumiskal" -- a word meaning to mix, from the Moorish era in Spain -- may point to Arab origins for the sauce.
Nonetheless, it took the arrival of tomatoes and chiles in Spain in the 16th century for romesco to acquire its present-day character.
And now, with a growing interest outside Spain, romesco's uses and variations are bound to keep multiplying.
2 dried nora chiles OR 1 ancho chile
4 tablespoons extra virgin olive oil
15 skinned hazelnuts or additional almonds
1 cup small cubes of stale sourdough bread
4 cloves garlic, peeled and sliced
2 jarred piquillo peppers, drained and chopped
1 medium ripe tomato, peeled, seeded and
chopped (about ⅔ cup)
⅔ cup dry white wine
1 tablespoon sherry vinegar
½ teaspoon smoked Spanish paprika, or to taste
Cut the chiles in half, place in a bowl and cover with boiling water, weighing them down with a plate to keep them submerged. Set aside for 30 minutes.
Heat oil in a small skillet over medium heat. Add the almonds, hazelnuts, and bread cubes and stir until they start to brown, 6 to 8 minutes. Add the garlic, and stir until lightly browned. Add the piquillo peppers. Remove from heat.
Drain the chiles, and remove stems and seeds. Chop the chiles, add them to the pan, heat and stir briefly. Add the tomato, stir and cook a minute or so until softened. Remove from heat.
Transfer to a food processor or a blender and pulse until a rough paste is formed. With the machine running, slowly pour in the wine. Turn off the machine, add vinegar, paprika and salt, to taste, then pulse briefly to blend. The sauce will have a slightly nubbly texture.
Yield: 1½ cups.
Fluke with Romesco and Potatoes
4 tablespoons extra virgin olive oil
1½ pounds large Yukon gold potatoes, peeled and diced
½ cup romesco sauce (see recipe)
1 cup fish stock or water
½ cup dry white wine
2 pounds fluke or halibut fillets, skinless, in 6 pieces
1 tablespoon finely minced parsley
Heat the oil over medium heat in a sauté pan or shallow stovetop casserole large enough to hold the fish in a single layer. Add the potatoes and sauté until they start to become crusty and brown, about 15 minutes. Season with salt. Stir in the romesco sauce, stock, and wine. Bring to a simmer. Add the fish, season with salt. The fish should be barely covered with the liquid. Cook gently just until the fish is cooked, about 15 minutes. Sprinkle with parsley. Serve from the pan or casserole, if possible, or transfer to a serving dish.
Yield: 6 servings.
Source: Adapted from Peix, Cuina i Tradicio, by David Sole i Torne