Chicken soup is strong medicine and, like most pharmaceuticals, compounded under lengthy, complex, covert conditions. Saving lives is serious business.

But certain afflictions — winter, flu season and empty-fridge syndrome — call for fast-tracking. Heath care providers take note: Though chicken soup is best rendered from whole bird, from carrots and turnips and celery, from bay leaf and dill frond, there is another way: water, onion, cutlet.

Not flashy but efficacious. Leave on the papery onion skin; it makes the shortcut even shorter and tints the broth a “long-simmered” caramel.

Slurp, or stir into soothing tortilla soup. See results. No one — not grandma, not Big Pharma — need know your secret.

Tortilla Soup

Prep: 30 minutes

Cook: 50 minutes

Makes: 6 servings

1 whole boneless, skinless chicken breast (1-pound), split into 2 halves

1 onion, skin on, halved

6 cups cold water

Kosher salt

1 tsp. freshly ground black pepper

2 Tbsp. mild oil

1 onion, roughly chopped

2 cloves garlic, smashed

2 chipotle chilies in adobo, fished from the can along with 2 tablespoons adobo sauce

1 box (28 ounces) or can diced tomatoes

3 cups grated cheddar

1 avocado, cut into small cubes

1 lime, cut into 6 wedges

Tortilla chips

Poach: Settle chicken and halved onion in a medium saucepan. Pour in water and sprinkle in 2 teaspoons salt. Bring to a boil; skim off any foam. Add black pepper, lower heat and simmer until chicken is fork-tender, about 20 minutes. Pull out chicken. When cool enough to handle, shred.

Brown: Meanwhile, heat oil in a separate saucepan. Tumble in chopped onion, garlic and a pinch of salt. Cook, stirring, until golden brown, about 8 minutes.

Swirl: Scoop onion and garlic into the blender. Add the chipotle chilies and their sauce, and the tomatoes. Swirl smooth. Strain this mix into the onion-browning saucepan; cook, covered, over medium-low heat until thick, about 15 minutes.

Toss: Toss together cubed avocado, 1/2 teaspoon salt and a squeeze of lime.

Simmer: Strain the broth, discarding the halved onion and other solids. Add broth to the saucepan with the thickened tomato. Cook 5 minutes. Add shredded chicken and heat through, about 1 minute.

Serve: Heap 1/2 cup grated cheese into each of 6 bowls. Scoop in hot soup. Scatter on avocado and a handful of broken tortilla chips. Serve with lime.