Black Bean Veggie Burger

Ingredients

• 2 cans black beans (15-ounce cans)
• 5 button mushrooms, sliced
• 1 tablespoon chili powder
• 1 tablespoon cumin
• 1 cup water
• 1 teaspoon dried oregano, crumbled
• 1 egg
• 1/3 cup plain dry bread crumbs
• 1/4 teaspoon cayenne pepper
• 3 tablespoons olive oil
• 1/2 cup onion (finely diced)
• 3 cloves garlic (minced)
• 4 slices cheese (optional)
• 4 hamburger buns