Mexican Bean and Tortilla Soup (Sopa Tarasca) Recipe

Ingredients

• 3 tablespoons vegetable oil, divided
• 2 pasilla chile peppers - stems, seeds, and veins removed
• 4 (6 inch) corn tortillas, cut into thin strips
• 1 Roma tomato
• 2 serrano peppers, or to taste
• 1 cup water
• 1/2 small onion, sliced
• 4 cups black beans, with liquid
• 1 pinch ground dried oregano
• salt to taste
• 3 tablespoons grated Cotija cheese, or to taste