Black Bean Mushroom Burgers

INGREDIENTS

• 1 Tablespoon canola oil, plus more for brushing
• 1 cup finely chopped onion
• 8 ounces cremini mushrooms, finely chopped
• 1 clove garlic, minced
• ½ teaspoon cumin
• ½ teaspoon smoked paprika
• 4 slices whole wheat sandwich bread, lightly toasted
• 15-ounce can black beans, rinsed and drained
• 2 ounces (about ½ cup) shredded cheddar cheese
• Salt and freshly ground black pepper
• 4 English muffins, sandwich pockets, or hamburger buns, split and toasted
• Salsa and sour cream, for serving (optional)