---
title: "Roasted Butternut Squash Soup with Crispy Sage and Brown Butter"
created: 2025-09-30 10:00
author: Amelia Fontaine
keywords: butternut squash, soup, brown butter, sage, autumn, roasting
description: Roasting vs steaming for depth, brown butter science, sage frying technique, and a full recipe with variations for a perfect autumn soup.
---

# Roasted Butternut Squash Soup with Crispy Sage and Brown Butter

The question with any squash soup is whether to roast the squash first or to steam or boil it. The answer, if you want the best-tasting soup, is always to roast. Steaming produces a pale, sweet, slightly watery result. Roasting produces caramelisation and depth that dramatically change what the soup can be.

The science is the Maillard reaction again: sugars in the squash combine with amino acids at high heat to produce hundreds of new flavour compounds. Squash is particularly susceptible to this because of its high sugar content. Roasted at 200°C until the cut surfaces are deeply golden and sticky, a butternut squash is a fundamentally different ingredient from a boiled one.

The brown butter amplifies this in a direction that seems designed for this vegetable specifically.

## Brown Butter

*Beurre noisette* — noisette meaning hazelnut, for the colour and aroma — is butter that has been cooked until the milk solids brown. The transformation happens in three stages:

1. Butter melts and the water begins to evaporate (you hear it fizzing).
2. The milk solids separate and begin to colour. The butter goes from opaque and milky to clear and golden.
3. The milk solids turn brown and the butter smells of toasted hazelnuts and toffee. This is the goal.

The danger: stage 3 transitions to stage 4 (burning) in about 30 seconds. Watch it constantly and remove from the heat the moment it smells right — it will continue to colour from the residual heat of the pan.

Brown butter adds a toasted, nutty complexity to anything that contains cream or dairy. On soup, drizzled over at serving, it is remarkable.

## Sage Crisps

Sage fried in butter or oil becomes a completely different ingredient: the volatile aromatic compounds that can make fresh sage taste slightly medicinal transform into something woody and resinous and addictive. Fried sage crisps are one of the best things you can put on soup, pasta, risotto, or gnocchi.

Heat a shallow layer of olive oil or clarified butter in a small pan until a sage leaf sizzles immediately on contact. Fry the leaves in batches for 30–45 seconds until darkened and crisp — they continue to crisp as they drain. Remove to kitchen paper immediately. They keep for several hours at room temperature.

## The Recipe (serves 4)

**Ingredients:**
- 1 large butternut squash (about 1.2kg), halved, seeds removed
- 1 large onion, roughly chopped
- 4 cloves garlic, unpeeled
- 750ml vegetable or chicken stock, warm
- 100ml double cream
- 3 tbsp olive oil
- Salt, pepper, nutmeg

**For the brown butter:**
- 80g unsalted butter
- A handful of fresh sage leaves

**Method:**

Brush the squash halves with 2 tablespoons of olive oil. Season generously with salt and pepper. Place cut-side down on a baking tray with the unpeeled garlic cloves and roast at 200°C for 45–55 minutes until the cut surface is deeply golden and the flesh is completely tender. Cool slightly.

Meanwhile, soften the onion in 1 tablespoon of olive oil in a large pot over medium heat until translucent and sweet, about 12 minutes.

Scoop the squash flesh from the skin. Squeeze the roasted garlic from its skins. Add both to the pot with the onion. Add the stock and bring to a simmer for 5 minutes.

Blend until completely smooth — a high-powered blender produces the best result; use a hand blender if that's all you have. Add the cream, a generous grating of nutmeg, and more salt and pepper. Taste carefully.

**To serve:** Reheat the soup gently if needed. Ladle into warm bowls. Make the brown butter in a small pan, watching carefully, and pull off the heat at hazelnut colour. Add the sage leaves to crisp in the same pan (the butter will sizzle vigorously). Drizzle brown butter over each bowl and top with crispy sage.

## Variations

**Spiced version**: Add 1 tsp ground cumin, ½ tsp smoked paprika, and a pinch of chilli to the onion as it softens. Finish with a swirl of yoghurt instead of cream, and toasted pumpkin seeds instead of sage.

**Thai-inspired**: Replace the cream with coconut milk. Add a stalk of lemongrass and a slice of galangal (or ginger) while blending, then strain. Finish with lime juice and fresh coriander.

**The bread bowl**: Hollow out a small round sourdough loaf and serve the soup inside it. Theatrical and more satisfying than it has any right to be.

The plain version, with brown butter and sage, is my preferred autumn lunch: made on a Sunday, reheated during the week, always excellent. The depth from the roasting means it doesn't need elaborate garnishes — the soup itself is doing most of the work.
