This simple, meat-free spin on tortilla soup is all about the ancho chilies. Anchos are dried ripe poblano chilies with a mild heat balanced by notes of tobacco, cocoa and dried fruit. The agave nicely rounds out the flavors 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.