Equipment
Ingredients
Sauce Base
- 225 g unsalted butter, chilled
- 100 g red onion, thinly sliced
- 2 garlic, thinly sliced
- 8 shiitake mushroom stems
- 75 g tomato, coarsely chopped
- 1 bay leaf
- 6 g black peppercorns
- 80 ml balsamic vinegar
- 80 ml water
- 1 g salt, to taste
- 1 g black pepper, to taste
Nutrition (per serving)
Method
Melt 25g of the butter in a large saucepan over medium heat.
Add the sliced red onion, garlic, shiitake stems, chopped tomato, bay leaf, and peppercorns to the pan. Sauté for 6 minutes until the vegetables are soft but not browned.
Pour in the balsamic vinegar and water. Increase the heat to medium-high and simmer for approximately 8 minutes until the liquid reduces to a syrupy consistency.
Lower the heat. Gradually whisk in the remaining 200g of cold butter a few pieces at a time, ensuring each addition is fully emulsified before adding more.
Pass the sauce through a fine sieve into a clean container to remove solids. Season with salt and black pepper to taste.
Keep the sauce warm over a double boiler (approx 50-60°C / 122-140°F) until ready to serve.
Chef's Notes
- Using cold butter is essential for a stable emulsion; softened butter will melt into oil too quickly.
- Shiitake stems provide deep umami but are discarded after straining.
Storage
Refrigerator: 72 hours — Sauce may separate when chilled; must be gently reheated.
Reheating: Warm gently over a double boiler while whisking to maintain the emulsion.
