Cheese-topped Mushrooms and Lentils

Name: Cheese-topped Mushrooms and Lentils
Prep time: 15 min
Cook time: 40 min
Total time: 55 min
Cuisine: European
Ingredients: 1 cup red-orange lentils (dried); 1 onions; 1 carrots; 1 stalk celery; 1 clove garlic; 16 button (white) mushrooms; 3 tbsp olive oil; 2/3 cup water; 1 tbsp Parsley and Garlic Base; 1 1/4 cup Gruyère cheese; 1 pinch salt; ground pepper to taste