Pecan & Mushroom Burgers

Place bulgur and 1/4 teaspoon salt in a small bowl. Pour the boiling water over, cover and set aside until the water is absorbed, about 20 minutes. Drain in a sieve, pressing out excess liquid.

Meanwhile, heat 2 teaspoons oil in a large nonstick skillet over medium heat. Add mushrooms, onion and remaining 1/2 teaspoon salt; cook, stirring, until the vegetables are softened, 8 to 10 minutes. Stir in vinegar. Immediately transfer the mixture to a plate and let cool to room temperature, about 30 minutes.

Toast pecans in a small dry skillet over medium-low heat, stirring, until fragrant, 4 to 6 minutes. Transfer to a plate to cool.

Prepare Blue Cheese Sauce, if using.

Combine the vegetable mixture and pecans in a food processor; pulse briefly until coarsely chopped. Add egg and the bulgur; pulse briefly, scraping down the sides if necessary, until the mixture is cohesive but roughly textured. Transfer to a bowl; stir in breadcrumbs and pepper. Mix well.

With dampened hands, form the mixture into eight 1/2-inch-thick patties, using about 1/2 cup for each.

Using 2 teaspoons oil per batch, cook 4 patties at a time in a large nonstick skillet over medium heat until evenly browned and heated through, about 4 minutes per side. Meanwhile, split and toast buns, if using, to serve the burgers on. Garnish the burgers with watercress and the cheese sauce, if desired.