This simple, meat-free spin on tortilla soup is inspired by a recipe from the late Patricia Quintana, chef, author and authority on Mexican cooking. Anchos chilies—dried ripe poblanos with a mild heat balanced by notes of tobacco, cocoa and dried fruit—drive the rich flavor and deep color of the soup. The agave nicely rounds out the earthiness with a touch of sweetness, so don’t omit it. If you don’t have any on hand, use 1 teaspoon white sugar instead. We like to top each serving with diced avocado and crumbled queso fresco.