Mushroom Sauce

By Flourish Original Recipe October 27, 2026 2 min read Lire en français

A rich, savoury mushroom sauce that pairs perfectly with the scaloppini on the previous page. Spoon it over the cutlets, then gently reheat everything together just before serving so the flavours come together.

Base Ingredients

  • 900 g (2 lb) mixed mushrooms, (see table below)
  • 2 medium yellow onions, diced (≈ 400 g)
  • 3 cups (750 ml) chicken stock, homemade if available
  • 2 tbsp. avocado oil
  • 2 tbsp. butter

Finishing Ingredients

  • 1 cup (250 ml) cream—35% for a classic rich sauce or 15% for a lighter version
  • 2 tbsp lion’s mane mushroom powder
  • Salt and pepper, to taste

Instructions

Heat the oil and butter in a wide skillet over medium heat. Add the onions and cook, stirring occasionally, until soft and translucent, 8–10 minutes. Transfer to a bowl.

In the same pan, fry the mushrooms one variety at a time, following the timing in the table below. Season each batch lightly with salt as it goes into the pan, then transfer to the bowl, leaving as much oil behind in the pan as you can.

Return the onions and mushrooms to the pan, add the stock, and simmer 8–10 minutes.

Stir in the cream, then whisk in the mushroom powder. Simmer 1–3 minutes until glossy and thickened. Season to taste.

Makes about 1 litre, enough for the full batch of cutlets from the previous page.

Suggested Mushroom Mix

Amount

Cut

Fry Time

King oyster / trumpet

300 g

Thick rounds

7–8 minutes, dense; you want a real sear

Oyster mushrooms

300 g

Torn or sliced

3–4 minutes, delicate; watch closely

Cremini (baby bella)

300 g

Sliced

5–6 minutes

 

Roughly equal amounts by weight, any mix works. Swap in fresh porcini when available (cook like cremini). With dried porcini, rehydrate 20 minutes in warm water, chop, and strain the soaking liquid into the stock.

Option

Make it a day ahead: Cook through step 3, then cool and refrigerate overnight. The next day, reheat gently and continue with step 4, adding the cream and mushroom powder.

Other Thickeners

No lion’s mane powder on hand? Either of these works well in its place. Mixed with cold water first; never add the starch directly into the hot sauce.

Arrowroot (2 tbsp. + ¼ cup cold water): a lighter, neutral option.

Cornstarch (2–3 tbsp. + ¼ cup cold water): a classic, reliable choice.