Egyptian Red Lentil Soup

Ingredient:

• 2 tablespoons unsalted butter
• 1 medium onion, chopped
• 2 carrots, finely chopped
• 3 celery ribs, finely chopped
• 3 garlic cloves, thinly sliced
• 1 teaspoon ground cumin
• 1/2 teaspoon ground coriander
• 1/2 teaspoon ancho chile powder
• 1 pound tomatoes, seeded and diced
• 2 cups red lentils (14 ounces)
• Kosher salt
• Plain yogurt, lemon wedges and warm pita, for serving