Lentil Potato Soup with Brown Butter and Fried Sage

Lentil potato soup with brown butter and fried sage delivers creamy comfort with a luxurious finishing touch that transforms simple ingredients into something restaurant-worthy. This soup is ready in 45 minutes, naturally thickens as it cooks, and tastes even better the next day.

What Makes This Lentil Potato Soup with Brown Butter and Fried Sage Special

The brown butter and fried sage topping is what elevates this from everyday soup to something truly special; the nutty, aromatic butter with crispy sage leaves adds incredible depth.

Brown lentils and starchy potatoes break down slightly as they simmer, creating a naturally creamy texture without any cream or blending required. The lentils provide plant-based protein and the potatoes add satisfying heartiness, making this filling enough to be a complete meal.

The soup base is simple and earthy, which lets the brown butter shine when you drizzle it on top. It’s a one-pot wonder that requires minimal prep and tastes like you spent hours in the kitchen.

Ingredients

You need humble pantry staples plus fresh sage for that show-stopping finish.

For the soup:

• 2 tablespoons olive oil
• 1 large onion, diced
• 3 celery stalks, diced
• 3 carrots, peeled and diced
• 4 garlic cloves, minced
• 1 cup brown or green lentils, rinsed
• 1 1/2 pounds (680g) Yukon Gold potatoes, peeled and cut into 1/2-inch cubes
• 6 cups vegetable broth
• 2 bay leaves
• 1 teaspoon dried thyme
• Salt and black pepper to taste
• 2 tablespoons lemon juice

For the brown butter and fried sage:

• 4 tablespoons unsalted butter (or vegan butter)
• 15-20 fresh sage leaves
• Pinch of salt
• Extra virgin olive oil for drizzling (optional)

Yukon Gold potatoes have the perfect starch content to thicken the soup without making it gluey.

How to Make This Lentil Potato Soup with Brown Butter and Fried Sage

1. Heat the olive oil in a large pot or Dutch oven over medium heat.
2. Add the onion, celery and carrots; sauté for 8-10 minutes until the vegetables are softened and the onion is translucent.
3. Stir in the garlic and cook for 1 minute until fragrant.
4. Add the lentils and stir to coat them with the oil and aromatics.
5. Add the diced potatoes, vegetable broth, bay leaves and thyme.
6. Bring to a boil, then reduce heat to medium-low, cover partially and simmer for 30-35 minutes until the lentils are tender and the potatoes are soft and starting to break apart.
7. Remove the bay leaves and stir the soup; some of the potatoes should naturally mash into the broth, creating a thicker consistency.
8. Stir in the lemon juice and season generously with salt and pepper.
9. While the soup finishes, make the brown butter: melt the butter in a small stainless steel skillet over medium heat (stainless steel or light-colored pans let you see the browning clearly).
10. Continue cooking the butter, swirling the pan occasionally, for 4-6 minutes until the milk solids turn golden brown and it smells nutty; watch carefully as it can burn quickly.
11. Add the sage leaves to the browned butter; they’ll sizzle immediately and crisp up in 30-45 seconds.
12. Remove from heat immediately and add a pinch of salt.
13. Ladle the soup into bowls.
14. Spoon the brown butter and fried sage leaves over each serving, making sure everyone gets some crispy sage.
15. Finish with a drizzle of extra virgin olive oil if desired.

Substitutions/Variations

Red lentils will create a thicker, more porridge-like soup since they break down completely; adjust cooking time to 20 minutes. For a chunkier soup, use waxy potatoes like red potatoes that hold their shape better.

Make it vegan by using plant-based butter; it browns just as beautifully as dairy butter. For extra richness, stir in 1/2 cup of coconut milk or cashew cream before serving.

Add a handful of chopped kale or spinach in the last 5 minutes of cooking for more greens. Smoked paprika (1 teaspoon) added with the thyme gives a subtle smoky depth.

If fresh sage isn’t available, skip the fried sage and just drizzle the brown butter on top; it’s still delicious. You can also fry other herbs like rosemary or thyme leaves.

What to Serve With This Lentil Potato Soup with Brown Butter and Fried Sage

Crusty sourdough bread is essential for soaking up every drop of that brown butter; toasted with olive oil makes it even better.

A simple arugula salad with lemon vinaigrette adds peppery brightness that cuts through the richness of the brown butter.

Grated Parmesan cheese or nutritional yeast sprinkled on top adds a salty, umami boost that complements the nutty butter beautifully.

More Comforting Lentil Soup Recipes

My classic lentil soup with brown butter croutons also features brown butter but in crunchy crouton form for different texture.

Try my creamy white bean and lentil soup with garlic for another cozy, thick soup that’s perfect for cold days.

For a brothy, lighter option with fresh herbs, make my bright lemon lentil soup with dill and mint which has completely different but equally delicious flavors.

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