Why This Recipe Works

Two-Stage Potato Cooking: We simmer half the potatoes until they're fall-apart tender for body, then add the rest later so every spoonful includes satisfying cubes.
Rib-Sticking Without Heavy Cream: A modest splash of whole milk plus a quick purée of the soup base yields luxurious silkiness for a fraction of the calories.
Garlic Herb Croutons Baked, Not Fried: Cubes of day-old bread are tossed with olive oil, garlic, and herbs, then oven-roasted until crisp—no greasy stovetop splatter.
Kale Added in Stages: Tough stems go in early to soften, while delicate ribbons are stirred in off-heat so they stay emerald and vibrant.
Make-Ahead Friendly: Flavors deepen overnight, and the soup reheats beautifully for quick weeknight dinners.
Pantry Staples Only: No specialty items required—just humble produce and a handful of everyday seasonings.

Ingredients You'll Need

Great soup starts with great produce. Here's what to look for at the market, plus smart substitutions so you can cook on a whim.

Produce

Baby (or New) Potatoes: Thin, edible skins mean no peeling. Choose firm, smooth specimens the size of ping-pong balls. If you only have large russets, peel and dice them into ¾-inch cubes— they'll break down a bit more but still taste wonderful.
Lacinato Kale: Also called dinosaur kale, its bumpy leaves are sweeter and tenderer than curly kale. Strip the leafy parts from the thick ribs; save the ribs for homemade veggie stock. In a pinch, baby spinach wilts in beautifully, though add it only in the final two minutes.
Leek: One medium leek yields a gentle onion flavor without sharp bite. Look for bright white and light-green parts with no slimy spots. Sub 1 medium yellow onion if that's what you have.
Garlic: Fresh, plump cloves are essential. Skip the pre-minced jarred stuff; its flavor dulls in long-cooked soups.
Fresh Herbs: Parsley stems flavor the broth; leaves garnish. Thyme adds woodsy perfume—dried works at half the amount if fresh isn't available.

Pantry & Dairy

Low-Sodium Vegetable Broth: Control saltiness yourself. Chicken broth is fine for omnivores.
Whole Milk: Just enough to round out flavors; swap unsweetened oat milk for a vegan version.
Extra-Virgin Olive Oil: Use the good stuff for the crouton drizzle; everyday olive oil is fine for sautéing.
Sourdough or Country Loaf: Day-old bread is drier and soaks up garlicky oil without turning gummy. Even sandwich bread works, though you'll get daintier croutons.
Nutritional Yeast (optional): Adds subtle cheesy depth and B-vitamins. Completely optional but lovely.

How to Make Potato and Kale Soup with Garlic Herb Croutons for Warm Winter Evenings

1 Prep Your Mise en Place: Wash leek thoroughly, slicing it in half lengthwise and fanning the layers under cold water to remove hidden grit. Dice the white and light-green parts; reserve dark tops for stock. Scrub potatoes; cut half of them into ½-inch pieces and the other half into ¾-inch cubes, keeping them separate. Strip kale leaves from ribs; chop ribs finely and tear leaves into bite-size shards. Mince 4 garlic cloves for the soup and 2 for the croutons.

2 Build the Flavor Base: Heat 2 Tbsp olive oil in a heavy 4-quart Dutch oven over medium heat. Add diced leek and chopped kale ribs; sauté 4 minutes until translucent and fragrant. Stir in ½ tsp salt, ¼ tsp black pepper, and 2 tsp fresh thyme leaves (or 1 tsp dried). Add minced garlic; cook 30 seconds until you can smell its perfume but it hasn't browned.

3 Simmer the Potatoes: Pour in 5 cups vegetable broth and the smaller-cut potatoes. Increase heat to high; once boiling, reduce to a steady simmer and cook 10 minutes. These pieces will break down and naturally thicken the soup.

4 Create Velvety Body: Using an immersion blender, purée the soup right in the pot for 10–15 seconds. You're looking for a creamy texture with some potato chunks remaining; think rustic, not baby food. No immersion blender? Carefully ladle 2 cups into a countertop blender, blend until smooth, and return to pot.

5 Add Remaining Potatoes & Kale: Stir in the larger potato cubes and half of the torn kale leaves. Simmer 8–10 minutes more, until potatoes are just fork-tender and kale has wilted.

6 Finish with Milk & Final Kale: Reduce heat to low; pour in 1 cup whole milk and the remaining kale ribbons. Stir gently; cook 2 minutes until kale turns bright green. Taste and adjust salt and pepper. Keep the soup below a simmer once milk is added to prevent curdling.

7 Bake the Garlic Herb Croutons: While the soup simmers, preheat oven to 400°F. Toss 3 cups cubed sourdough with 2 Tbsp olive oil, 2 minced garlic cloves, ½ tsp dried oregano, ½ tsp smoked paprika, and ¼ tsp salt. Spread on a sheet pan; bake 10 minutes, stir once, then bake 5–7 minutes more until golden and crisp. They'll continue to harden as they cool.

8 Serve & Garnish: Ladle soup into warmed bowls. Top generously with garlic herb croutons, a sprinkle of fresh parsley, and an optional dusting of nutritional yeast or grated Parmesan. Drizzle with peppery olive oil and serve immediately.

Expert Tips

Temperature Matters

Never let the soup boil after adding milk; high heat can curdle dairy. A gentle steam and tiny bubbles around the edge are perfect.

Crouton Crunch Hack

Bake croutons while the potatoes simmer, then turn off the oven and leave the door ajar so they dry extra-crispy without burning.

Blender Safety

If using a countertop blender, fill it no more than halfway with hot soup, remove the center cap, and cover with a towel to release steam safely.

Revive Wilted Kale

Soak sad-looking kale in ice water for 15 minutes to perk it up. Dry thoroughly before adding to soup to avoid diluting flavors.

Flavor Lock

Let finished soup rest 10 minutes off-heat before serving. This brief pause allows the milk and potatoes to marry, deepening overall flavor.

Zero-Waste Twist

Save kale ribs, leek tops, and parsley stems in a freezer bag. When full, simmer 30 minutes with water for a fragrant vegetable stock.

Variations to Try

Smoky White-Bean Version: Stir in 1 can drained cannellini beans along with the larger potato cubes for extra protein; add ½ tsp smoked paprika to the broth.
Coconut-Ginger Vegan: Swap whole milk for ¾ cup full-fat coconut milk and add 1 Tbsp grated fresh ginger with the garlic for a bright, dairy-free twist.
Lemon Chicken & Rice: Replace half the potatoes with diced cooked chicken and ½ cup long-grain rice; finish with a squeeze of fresh lemon juice and zest.
Spicy Chorizo: Brown 4 oz crumbled Spanish chorizo before sautéing the leek; reduce salt elsewhere to balance the chorizo's seasoning.
Creamy Broccoli-Kale: Add 2 cups small broccoli florets with the second round of potatoes; purée an extra 5 seconds for a green-hued, extra-nutritious bowl.
Everything Bagel Croutons: Swap herbs for 1 Tbsp Everything Bagel seasoning before baking for an onion-garlic crunch with poppy-seed flair.

Storage Tips

Refrigerator

Cool soup completely, transfer to airtight containers, and refrigerate up to 4 days. Store croutons separately in a zip-top bag at room temperature so they stay crisp. When reheating, warm gently over medium-low heat, stirring often and thinning with a splash of broth or milk if needed.

Freezer

This soup freezes beautifully for up to 3 months, but omit the milk before freezing. Ladle cooled soup into freezer-safe containers, leaving 1 inch headspace. Thaw overnight in the fridge, then reheat and stir in milk during the final 2 minutes. Frozen croutons will get soggy; make a fresh batch when serving.

Frequently Asked Questions

Yes! Add broth, leek, kale ribs, and all potatoes to a 6-quart slow cooker. Cook on LOW 6 hours or HIGH 3 hours. Purée briefly with an immersion blender, then stir in kale leaves and milk; let stand 5 minutes before serving. Prepare croutons in the oven as directed.

Simply whisk in warm vegetable broth or milk, ¼ cup at a time, until you reach the desired consistency. Remember the soup will thicken slightly as it stands due to the potatoes releasing starch.

Absolutely. Sauté leek, kale ribs, and garlic on NORMAL heat. Add broth and smaller potato pieces; pressure cook on HIGH for 5 minutes with a quick release. Stir in larger potato cubes and kale leaves; use KEEP WARM for 10 minutes, then add milk and serve.

Swiss chard, beet greens, or mature spinach are excellent. For tougher greens like collards, increase simmering time by 5 minutes. For delicate arugula, stir in off-heat just before serving.

The soup itself is naturally gluten-free. For croutons, use sturdy gluten-free bread (brands like Schär or homemade). Bake 2 minutes longer, as GF bread tends to hold more moisture.

Yes—this recipe doubles easily in an 8-quart pot. Increase simmering times by 2–3 minutes to account for the larger volume. Freeze portions in quart containers for effortless future dinners.