This Chicken Pesto Soup is the kind of weeknight meal I reach for when I want something cozy, bright, and no-fuss. It feels comforting like a bowl of chicken soup, but the pesto and lemon lift the flavors so the soup never tastes heavy. I love that it comes together mostly in one pot — the Instant Pot makes the whole thing fast and hands-off, and the result is tender chicken, tender cauliflower “rice,” and a fragrant, herb-forward broth.

There’s a clean, springy feel from the basil pesto and lemon juice that keeps this soup from being cloying. At the same time, the vegetables and chicken make it substantial. If you’re watching starches or just want a lighter soup without sacrificing satisfaction, the cauliflower rice is a brilliant swap-in that keeps the texture pleasant.

I write this recipe the way I actually cook it: practical steps, short ingredient list, and tips for swaps and storage so you can make it any night of the week. Read through the notes if you want to tweak salt levels or change the protein — I’ll tell you what works and what to avoid.

What Goes Into Chicken Pesto Soup

Ingredients

1 small onion, chopped — builds the savory base; chop fine so it softens quickly.
2 small carrots, chopped — adds subtle sweetness and color; dice small for even cooking.
1 cup chopped celery — classic soup aromatics that give texture and flavor.
1 T butter — used for sautéing the aromatics and adding richness.
1 tsp. Italian Herb Seasoning — quick way to layer oregano/thyme/basil notes.
1/2 tsp. ground sage — earthy warmth; a little goes a long way.
1/2 tsp. ground thyme (see notes) — another savory herb to round the flavor.
salt and fresh-ground black pepper to taste — finish and balance the soup; adjust after stirring in pesto.
8 cups chicken broth (see notes) — the main liquid; quality matters for flavor.
3 T chicken soup base — concentrated boost of savory chicken flavor.
4 large boneless, skinless chicken breasts — the protein; will be cooked whole then shredded.
10.5 oz. package frozen cauliflower rice (see notes) — keeps the soup lighter and helps thicken a bit as it heats.
1/4 cup basil pesto (see notes) — finish for herb brightness and richness.
2 T fresh-squeezed lemon juice (see notes) — adds acidity to brighten the broth at the end.

Method: Chicken Pesto Soup

Remove the 10.5 oz. package of frozen cauliflower rice from the freezer and set it on the counter to begin thawing while you prepare the other ingredients.
Trim any excess fat from the 4 chicken breasts. Cut each breast lengthwise into 2 or 3 strips.
Finely chop the 1 small onion, 2 small carrots, and 1 cup chopped celery.
Set the Instant Pot to SAUTÉ (High). Add 1 T butter and melt.
Add the chopped onion, carrots, and celery to the pot and cook 2–3 minutes, until they begin to soften.
Stir in 1 tsp Italian Herb Seasoning, 1/2 tsp ground sage, 1/2 tsp ground thyme, and salt and fresh-ground black pepper to taste. Cook 1 minute to bloom the herbs.
Add 8 cups chicken broth, the 3 T chicken soup base, and the chicken breast strips to the pot. Secure the lid and set the pressure valve to SEALING. Set to MANUAL (High) for 6 minutes.
When the cook time ends, let the Instant Pot natural release for 10 minutes, then carefully move the valve to VENTING to release any remaining pressure. Open the lid.
Remove the cooked chicken pieces to a cutting board and set the Instant Pot to SAUTÉ (Low).
Add the frozen (partially thawed) cauliflower rice to the pot and cook at SAUTÉ Low for at least 5 minutes, stirring occasionally, until heated through and tender.
While the cauliflower rice cooks, shred the cooked chicken into bite-size pieces.
Add the shredded chicken back to the soup and cook about 3 more minutes to heat through.
Turn the Instant Pot off. Stir in 1/4 cup basil pesto and 2 T fresh-squeezed lemon juice. Taste and adjust salt and pepper if needed.
Serve immediately.

Why I Love This Recipe

Simple, dependable, and bright — that’s the short version. The cooking process is mostly hands-off once the chicken is in the Instant Pot, which makes it a perfect go-to for busy nights. The pesto at the end transforms the broth in a single stir: it adds fat, basil, and a little garlic-savory lift that makes the soup feel homemade and special without extra effort.

Texture matters here. The carrots and celery give a bit of chew, the cauliflower rice keeps things lighter than regular rice or pasta, and the shredded chicken soaks up the broth. It’s a bowl that feels nourishing and fresh at once, which is why I return to it when I want comfort without heaviness.

Swap Guide

Cauliflower rice — swap for 1 cup cooked rice or small pasta if you prefer more traditional starch (adjust cooking/finishing accordingly).
Chicken breasts — use 4 cups cooked, shredded rotisserie chicken if you’d rather skip pressure-cooking time.
Basil pesto — use sun-dried tomato pesto or a teaspoon of extra-virgin olive oil + handful of chopped fresh basil if you’re out of jarred pesto.
Chicken soup base — replace with 1½ tsp concentrated bouillon paste or 3 T miso + less salt for a different umami profile.

What’s in the Gear List

Instant Pot or electric pressure cooker — the recipe is written for one; it speeds up the cooking and keeps everything in one pot.
Cutting board and a sharp chef’s knife — for trimming and chopping the vegetables and chicken.
Measuring spoons and cups — to get the herb and broth quantities right.
Wooden spoon or heatproof spatula — for sautéing and stirring the cauliflower rice without scratching the pot.
Tongs or fork — handy when moving chicken to the cutting board for shredding.

Errors to Dodge

Overcooking the cauliflower rice — it should be tender, not mushy. Stir and watch during the sauté stage.
Skipping the natural release — letting the Instant Pot natural release for 10 minutes prevents the chicken from drying out and ensures even texture.
Adding pesto too early — pesto loses its fresh flavor with extended heat. Stir it in at the end off the heat.
Using low-quality broth — since broth is the main liquid, a weak broth makes the whole soup flat. Use a good chicken broth or stock.

Smart Substitutions

Broth — if you want lower sodium, use low-sodium chicken broth and increase the chicken soup base slightly or add salt at the end to taste.
Herb seasoning — if you don’t have an Italian blend, use a mix of dried oregano and basil (3:1) as a quick stand-in.
Chicken — turkey breast works the same way; adjust cook time minimally if the pieces are thicker.
Pesto — homemade or jarred both work; if homemade is olive-heavy, cut back to 3 T so it doesn’t overpower the soup.

Pro Tips & Notes

Timing & Prep

Set the cauliflower bag on the counter first so it thaws a bit while you chop. Finely dice the onion and carrots so they soften quickly during the 2–3 minute sauté. Cutting the chicken into strips speeds the pressure-cook stage and helps it cook evenly.

Flavor Balance

Always taste after stirring in the pesto and lemon. Pesto adds saltiness and oil; lemon brightens. You may need only a pinch more salt or none at all. If the broth tastes too concentrated after pressure cooking, add up to 1 cup of water or more broth to loosen it.

Herb Notes

The recipe uses a mix of Italian Herb Seasoning, sage, and thyme. If you want a fresher, greener flavor, finish with a couple of tablespoons of chopped fresh basil in addition to the pesto.

Storage & Reheat Guide

Cool the soup slightly, then transfer to airtight containers. In the fridge, it will keep 3–4 days. For longer storage, freeze in portions for up to 3 months — leave a little headspace in containers because liquids expand when frozen.

To reheat: thaw frozen portions overnight in the fridge or reheat from frozen on the stovetop over low-medium heat. If using the stovetop, bring gently to a simmer and stir frequently so the cauliflower rice doesn’t break down too much. In the microwave, reheat in 60–90 second bursts, stirring in between so the heat distributes evenly.

Common Qs About Chicken Pesto Soup

Can I make this on the stovetop instead of an Instant Pot? — Yes. Brown the aromatics in a heavy pot, add the broth and chicken strips, simmer gently until the chicken is cooked through (about 12–15 minutes depending on thickness), then proceed with the cauliflower rice and finishing steps.
Is this soup freezer-friendly? — Yes. Freeze in single-serving containers. When reheating, add a little extra broth or water if it thickens up during freezing.
What if I don’t have chicken soup base? — Use additional chicken broth and season with salt and a dash of soy sauce or miso for umami, but taste as you go.
Can I substitute fresh cauliflower for the frozen rice? — You can pulse fresh cauliflower in a food processor to make rice, but you’ll need to cook it slightly longer in the sauté step until tender.

Before You Go

Make a batch and you’ll see why this one sits in my rotation. It’s forgiving, flavorful, and comes together quickly with pantry-friendly components. If you tweak it — like swapping in rotisserie chicken or using a different pesto — leave a note in the comments so others can learn what worked. Enjoy the bowl.