Ingredients

• 2 teaspoons vegetable oil, or as needed
• 1 small onion, chopped
• 1 large clove garlic, minced
• 2 (15.5 ounce) cans black beans, rinsed and drained
• 1 cup chicken stock
• 5 fresh sage leaves
• water to cover
• ¼ cup freshly grated Parmesan cheese
• 2 tablespoons butter, softened
• ¼ cup half-and-half
• ¼ cup chopped green onion, or to taste
• 2 tablespoons grated Parmesan cheese, or to taste