Mushroom Soup with Brown Butter Walnuts & Crispy Sage
I’ve always loved browned butter and sage with pumpkin soup, but only recently had the idea to try it with mushroom soup instead. Low carb and just as delicious. Love it!
And the walnuts add all the crunch to take this from being just another mushroom soup, to something really special. When I did my recent photo shoot, this was the dish I was most excited to choose for lunch (and there were a lot of good options!).
If you have some exotic mushrooms, by all means go for it. But this soup is fabulous with humble button mushies from the supermarket.
enough for: 2
takes: 30 minutes
900g (2lb) mushrooms, sliced
6-8 tablespoons salted butter
2 cups chicken or veg stock
1 small bunch sage, leaves picked
2 handfuls walnuts
1. Heat 2 tablespoons of your butter with a little drizzle of oil in a medium saucepan on a medium high heat. The oil prevents the butter from burning. When the butter has melted, add the mushrooms and cook, stirring for 5 minutes or until mushies are starting to brown.
2. Add stock. Cover and bring to a simmer. Simmer, covered for 10 minutes, or until mushrooms are tender.
3. While the mushrooms are cooking, melt the remaining 4-6 tablespoons butter in a small frying pan on a medium high heat. When the butter starts to foam add the sage and walnuts and cook, stirring frequently for a few minutes until the walnuts are toasted and the butter goes a deep golden brown colour. Remove from the heat.
4. When the mushrooms are tender. Remove pot from the heat and puree soup using a stick blender. It’s up to you how smooth you make it. Taste soup and season with salt as needed.
5. Divide soup between two bowls and top with walnuts, sage and the beautifully nutty brown butter.
WINE MATCH: A big oaky chardonnay or an earthy pinot noir.
Variations & Substitutions
pantry-friendly – mushrooms = onions. Cook until onions are very soft before adding stock – about 10 minutes. Skip the sage.
more substantial (carb lovers) – Serve with crusty bread and butter or toss in some cooked pasta, quinoa or chickpeas after the soup has been pureed.
more substantial (low carb) – double the walnuts and / or use more butter. Or serve with almond bread.
more veg – soften an onion before browning the mushrooms. Add diced carrot and celery with the stock and simmer a little longer until the veg are tender.
extreme mushroom – add a small handful of dried porcini mushrooms with the stock. Or a few teaspoons porcini mushroom powder.
different mushrooms – fab also with large flat mushrooms (field), shittake, portabello or a mixture of mushies.
dairy-free – use extra virgin olive oil to crisp the sage and toast the walnuts. Serve with mayonnaise.
nut-free – replace walnuts with cooked chickpeas or sourdough bread crumbs or chunks.
no sage – the brown butter walnuts will work without. OR try thyme leaves or rosemary instead.
carnivore – add some cooked bacon or sausage after pureeing.
no stock – use a can of tomatoes + 1/2 cup of water as well – of soup too thick add extra water.
extra creamy – if you love extra creamy soups – add a drizzle of cream when pureeing the soup.
keto / ultra low carb – try this spinach soup.
Waste Avoidance Strategy
mushrooms – keep in the fridge in a brown paper bag. Once cooked will keep for weeks. And can be frozen raw or cooked.
butter – will keep in the fridge for weeks.
chicken or veg stock / walnuts – keep them in the pantry.
sage – best to use for another meal. Can be frozen but will wilt when defrosted.
Problem Solving Guide
bland – next time use more flavoursome stock. For now a little salt or some soy sauce will fix things.
too thick – add water or more stock until your happy. Bring back to a simmer before serving. Next time cover the soup while it’s simmering to reduce evaporation.
too watery – either simmer to reduce and thicken. Or add some almond meal, canned lentils, canned chickpeas or roast veg to thicken. Next time cook the mushrooms uncovered.
bitter – sounds like you took the butter too far. You can discard and start again or just swap it for extra virgin olive oil.
Yes! Just cook soup as per the recipe but keep the walnuts, sage and brown butter separately so they remain crisp. Will keep in the fridge for 2 weeks or can be frozen. To serve, bring soup back to a simmer and melt butter in a small frying pan.