Egyptian Red Lentil Soup

Name: Egyptian Red Lentil Soup
Ingredients: 2 tablespoons unsalted butter; 1 large onion, diced; 3 celery ribs, diced; 2 large carrots, diced; 4 garlic cloves, minced; 1 teaspoon ground cumin; ½ teaspoon ground coriander; ½ teaspoon chili powder; ½ teaspoon hot curry powder; 2 quarts chicken or vegetable stock; 1 14.5 ounce can diced tomatoes; 2 cups red lentils (if you can't find red lentils, you can use a different color, you just won't have this beautiful color and it might change the cooking times); Salt and pepper to taste