For the Salsa
2 lb. plum tomatoes, cored, and cut into 1⁄2” cubes
2⁄3 cup roughly chopped cilantro
6 serrano chiles, stemmed, seeded, and finely chopped
1 large white onion, finely chopped
Kosher salt, to taste
For the Beans and Rolls
1⁄2 cup lard or canola oil
4 cloves garlic, minced
1 small white onion, finely chopped
2 cups chicken stock
3 (15-oz.) cans pinto beans, drained and rinsed
Kosher salt and freshly ground black pepper, to taste
4 bolillos (see Mexico’s Daily Breads) or kaiser rolls, split
12 oz. queso Oaxaca, grated (available at mexgrocer.com)
To make the salsa, combine tomatoes, cilantro, chiles, and onion in a bowl, and season liberally with salt; fold gently to combine. Cover, and refrigerate, for about 1 hour.
To make the refried beans, heat lard in a 12″ skillet over medium-high heat. Add garlic and onion, and cook, stirring, until soft, about 8 minutes. Add stock and beans, and cook, stirring and mashing, until almost all beans are smooth and mixture is slightly soupy, about 5 minutes. Season with salt and pepper, and keep warm.
Heat broiler to high. Using your fingers, scoop out and discard the insides of rolls, leaving a 1⁄2“-thick shell. Place roll halves on a foil-lined baking sheet with their cut sides up, and broil until lightly toasted, about 2 minutes. Pour about 1⁄2 cup refried beans over each roll half so that the beans are spilling over the edges, and then sprinkle with cheese. Return to broiler, and heat until beans are heated through and cheese is just melted, but not browned, about 2 minutes. Transfer one roll half to each serving plate, and top each with a couple large spoonfuls of salsa. Serve immediately.