Beurre Rouge — Red Wine Butter Sauce

Ingredients

• For the reduction
• 3 shallots, brunoise — minced to near-dissolution
• 250 ml dry red wine, Pinot Noir or Cabernet Franc; avoid heavily tannic varieties
• 2 tbsp red wine vinegar
• For the sauce
• 250 g unsalted butter, cold, cut into 2 cm cubes

Method

1. 1
   Combine the brunoise shallots, red wine, and red wine vinegar in a small saucepan over medium heat. Reduce until nearly dry — approximately 2 tablespoons of intensely purple, syrupy liquid remain. This concentrated fond is the flavour base of the entire sauce.
2. 2
   Reduce heat to the lowest possible setting. The pan must hold within 58–62 °C throughout the next stage. This is where the dish lives or dies: too hot and the butterfat separates into purple oil and milk solids; too cold and the butter solidifies rather than emulsifying. Add the cold butter cubes one at a time, whisking each piece fully into a glossy, opaque emulsion before introducing the next.
3. 3
   Continue until all 250 g of butter is incorporated. The finished sauce should be opaque, deep crimson-purple, glossy, and pourable — tasting of wine and butter in equal measure, with savoury shallot depth and vinegar lift.
4. 4
   Pass through a fine chinois for a smooth, restaurant finish, or leave unstrained for a more rustic character. Serve immediately, or hold in a warm spot on the side of the stove, whisking occasionally, at 50–65 °C, and use within 30 minutes.