Equipment
* optional
Ingredients
Aromatic Base
- 35 g unsalted butter, chilled
- 115 g shallots, finely minced
- 3 garlic, thinly sliced
- 10 shiitake mushroom stems
- 85 g roma tomato, finely diced
- 1 bay leaf
- 4 g black peppercorns, whole
Reduction & Finish
- 90 ml balsamic vinegar
- 70 ml water
- 215 g unsalted butter, cold, cubed
- 2 g kosher salt, to taste
- 1 g black pepper, freshly cracked
Nutrition (per serving)
Method
In a heavy-bottomed saucepan, melt the initial 35g of butter over medium heat until foaming. Add the minced shallots, garlic, shiitake stems, diced tomato, bay leaf, and peppercorns. Sweat the aromatics for 6-8 minutes until the shallots are translucent and soft, ensuring they do not take on any brown color.
Pour in the balsamic vinegar and water. Increase the heat to medium-high (approx. 95°C/203°F) and bring to a simmer. Reduce the liquid by approximately 60% until it achieves a thick, syrupy consistency that coats the back of a spoon.
Lower the heat to the absolute minimum. Begin whisking in the 215g of cold, cubed butter one or two pieces at a time. Whisk vigorously to create a stable emulsion, adding more butter only once the previous pieces have completely melted into the sauce.
Pass the sauce through a fine-mesh chinois into a clean bowl or the top of a double boiler. Press firmly on the solids to extract all the flavorful essences. Season with kosher salt and freshly cracked pepper to taste.
Hold the sauce in a double boiler over warm (not boiling) water at approximately 45°C-55°C (113°F-131°F) until ready to serve. Whisk occasionally to maintain the emulsion.
Chef's Notes
- The quality of the balsamic is paramount. Avoid 'balsamic glazes' which contain thickeners; use a true fermented vinegar.
- Always use unsalted butter to maintain total control over the seasoning profile.
- For a restaurant-quality finish, add a tiny squeeze of fresh lemon juice at the very end to brighten the heavy fats.
Storage
Refrigerator: 5 days — Store in an airtight container; the emulsion will solidify and must be gently rewarmed.
Reheating: Gently warm over a bain-marie while whisking; do not bring to a boil.
