Instant Pot Sourdough Minestrone Soup

Name: Instant Pot Sourdough Minestrone Soup
Prep time: 15 min
Cook time: 22 min
Total time: 37 min
Yield: 6 servings
Cuisine: Italian
Ingredients: 2 cups (cubed) (140 g) sourdough bread, cut into ½-inch cubes; 3 tablespoons (45 ml) olive oil; 1 large (225 g) yellow onion, large, diced (about 1½ cups); 3 cloves (15 g) garlic cloves, minced; 2 medium (240 g) carrots, medium, diced (about 1½ cups); 2 stalks (120 g) celery stalks, diced (about ¾ cup); 1 large (220 g) zucchini, large, diced (about 1½ cups); 28 oz (800 g) canned diced tomatoes (with juice), with juice; 6 cups (1425 ml) vegetable broth; 2 cans (15 oz each) (900 g) cannellini beans, canned, drained and rinsed; 3 cups (loosely packed) (90 g) fresh spinach; ½ cup (loosely packed) (15 g) fresh basil leaves, chopped; salt, to taste; black pepper, freshly ground, to taste; ¼ cup (grated) (25 g) Parmesan cheese, grated, for serving (optional)

From the MyKitchenBank Kitchen

A hearty, tangy Italian vegetable soup made in the Instant Pot, featuring white beans, fresh vegetables, and diced sourdough bread that adds a subtle sour note and satisfying texture to a rich tomato and herb broth.

Prep: 15 min
Cook: 22 min
Wait: 11 min
Total: 48 min
Makes: 6 servings (about 9 cups)

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Ingredients

6 servings

2 cups (cubed) (140 g) sourdough bread, cut into ½-inch cubes
3 tablespoons (45 ml) olive oil
1 large (225 g) yellow onion, large, diced (about 1½ cups)
3 cloves (15 g) garlic cloves, minced
2 medium (240 g) carrots, medium, diced (about 1½ cups)
2 stalks (120 g) celery stalks, diced (about ¾ cup)
1 large (220 g) zucchini, large, diced (about 1½ cups)
28 oz (800 g) canned diced tomatoes (with juice), with juice
6 cups (1425 ml) vegetable broth
2 cans (15 oz each) (900 g) cannellini beans, canned, drained and rinsed
3 cups (loosely packed) (90 g) fresh spinach
½ cup (loosely packed) (15 g) fresh basil leaves, chopped
salt, to taste
black pepper, freshly ground, to taste
¼ cup (grated) (25 g) Parmesan cheese, grated, for serving (optional)

Equipment (5)

6-quart Instant Pot
10-inch skillet or sauté pan
Cutting board
Chef's knife
Wooden spoon

Steps

Before you start

Cut 4–5 oz (115–140 g) of sourdough bread into ½-inch cubes (you'll need about 2 cups)
Dice the onion, carrots, celery, and zucchini; mince the garlic; chop fresh basil
Have an extra ½ cup of vegetable broth on hand in case the soup reduces more than expected
If using dried beans, cook them ahead (or use two 15-oz cans, drained)

1
Toast sourdough croutons
- Heat a 10-inch skillet over medium-high heat.
- Add 1 tablespoon (15 ml) of olive oil.
- Once it shimmers, add the sourdough cubes and toast, stirring occasionally, for 3–4 minutes until they are golden brown with crispy edges.
- This prevents the bread from becoming mushy in the hot broth.
- Transfer the toasted cubes to a plate and set aside.
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Ready when: Bread cubes are golden brown with crispy edges
Tip: Toasting the bread prevents it from disintegrating in the broth and preserves the pleasant texture—do not skip this step
2
Sauté aromatics
- Switch to the Instant Pot and select sauté mode on high heat.
- Add the remaining 2 tablespoons (30 ml) of olive oil.
- Once it shimmers, add the diced onion and celery, stirring occasionally.
- Cook for 3 minutes until the onion becomes translucent and the celery softens slightly.
- Add the minced garlic and cook for 1 minute more until fragrant and light golden.
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Ready when: Onion is translucent, garlic is fragrant and light golden
Tip: Don't rush the garlic step—it builds the flavor foundation of the soup
3
Add remaining vegetables
- Stir in the diced carrots and zucchini.
- Cook for 1 minute more, stirring often, to coat them with oil and allow their flavors to begin releasing into the pot.
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Ready when: Vegetables are evenly coated with oil and beginning to release aroma
4
Deglaze and build broth base
- Pour in the 6 cups (1425 ml) of vegetable broth and the canned diced tomatoes with their juice.
- Stir well, scraping the bottom of the pot with a wooden spoon to release any browned bits (fond) stuck to the surface—this adds deep, savory flavor.
- The pot should be about three-quarters full.
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Ready when: Liquid is well mixed and browned bits are scraped up
Tip: Deglazing ensures all the flavorful caramelized bits from sautéing are incorporated into the soup base
5
Pressure cook the vegetables
- Turn off sauté mode.
- Close the lid firmly, making sure the pressure release valve is set to sealing (not venting).
- Select high pressure and set the timer for 8 minutes.
- The pot will take 2–3 minutes to reach full pressure before cooking begins.
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Ready when: Pressure indicator shows the pot is at full pressure
Tip: Verify the pressure release valve is set to sealing, or the pot will not build pressure and the vegetables will not cook properly
6
Release pressure naturally
- When the 8-minute timer sounds, turn off the Instant Pot and let it sit undisturbed for 10 minutes.
- The pressure will drop gradually and the pressure indicator will fall.
- This natural release prevents the vegetables from overcooking and turning mushy.
- After 10 minutes, carefully turn the pressure release valve to venting to release any remaining steam.
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Ready when: Pressure indicator has fully dropped and no steam escapes when the valve is opened
Tip: Use natural release (not quick release) to keep the vegetables from becoming mushy—this is worth the wait
7
Add beans and spinach
- Carefully remove the lid (steam will still be hot).
- Select sauté mode and add the drained cannellini beans, stirring gently to combine.
- Add the fresh spinach in two or three batches, stirring gently after each addition until the leaves wilt completely and turn dark green.
- This should take 2–3 minutes total.
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Ready when: All spinach is wilted and dark green; beans are heated through
Tip: Add spinach in batches so it wilts evenly without overcrowding the pot and causing it to splatter
8
Add bread and fresh basil
- Turn off sauté mode.
- Gently stir in the toasted sourdough croutons and the chopped fresh basil.
- Taste the soup and season with salt and freshly ground black pepper as needed.
- Let the pot sit for 1 minute to allow the bread to absorb some of the broth and soften slightly while still maintaining its slight structure.
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Ready when: Bread is warmed through and slightly softened; basil is evenly distributed
Tip: Always add fresh basil at the very end—add it earlier and its bright flavor will fade into the hot broth
9
Ladle and serve
- Ladle the soup into bowls, making sure each serving gets a good mix of vegetables, beans, and toasted bread cubes.
- Drizzle or sprinkle grated Parmesan cheese on top (about 1–2 teaspoons per serving) if desired.

Good to know

Tips

For a chunkier, rustic soup, cut vegetables into ¾-inch pieces. For a finer, more classic minestrone texture, cut them into ½-inch pieces
If you prefer a brothier soup, add an extra ½ cup of vegetable broth. For a thicker, stew-like consistency, reduce the broth to 5½ cups
Fresh basil is essential and should not be omitted or replaced with dried basil—it brightens the soup at the very end and makes a significant difference
This soup reheats beautifully and tastes even better the next day once all the flavors have melded together. Make a double batch and freeze in portions for easy weeknight dinners

Make ahead

You can toast the sourdough cubes up to 1 day ahead and store them in an airtight container at room temperature. You can also prep all vegetables up to 4 hours in advance and store them in separate covered containers in the refrigerator—this makes the Instant Pot cooking even faster on the day you serve it.

Storage & reheating

Room temperature: up to 1 hour (in a covered pot). Refrigerator: up to 4 days in an airtight container. Freezer: up to 3 months in airtight freezer-safe containers or bags (the sourdough cubes will soften but the soup remains delicious). To reheat from frozen, thaw overnight in the refrigerator and warm in the Instant Pot on sauté mode or in a pot on the stovetop over medium heat until steaming, about 8–10 minutes.

Substitutions

cannellini beans, canned → Great Northern beans, navy beans, or white beans (fresh, cooked, or canned). Any white bean works well here; they have a mild flavor that doesn't compete with the basil and sourdough
fresh spinach → Kale, Swiss chard, or arugula. If using kale, add it 1–2 minutes earlier in the sauté since it's heartier and needs more time to wilt
sourdough bread → Whole wheat bread, rye bread, or any crusty artisan bread. Sourdough's tang is optional; use any good bread. Avoid soft white bread, which will fall apart
vegetable broth → Chicken broth or vegetable stock. Chicken broth will give a slightly richer flavor, though it moves the soup away from vegetarian territory