Sauce Marchand de Vin — Red Wine Shallot Reduction

Ingredients

• 2 shallots, finely chopped
• 200 ml full-bodied red wine, Bordeaux or equivalent; drinkable quality
• 200 ml demi-glace, equal in volume to the reduced wine
• 30 g cold unsalted butter, cut into small cubes
• 1 squeeze lemon, fresh juice
• 1 tbsp flat-leaf parsley, finely chopped
• 15 ml residual steak pan fat, from the cooked steak pan

Method

1. 1
   Return the steak pan to a medium-low heat. Add the finely chopped shallots to the residual fat and sweat, stirring frequently, until completely soft and translucent — they must not take on any colour. The shallots are ready when they offer no resistance and smell sweet rather than sharp.
2. 2
   Pour the red wine into the pan and raise the heat to a vigorous boil. Reduce by three-quarters in a wide pan, allowing rapid evaporation. This is where the dish lives or dies: under-reduction leaves raw tannin and alcoholic sharpness in the finished sauce; the reduction is complete only when the wine has condensed to a syrupy, deeply coloured glaze and its sharp, alcoholic edge has entirely cooked away.
3. 3
   Add the demi-glace — equal in volume to the reduced wine — and bring to a gentle simmer. Hold at a light simmer for 5 minutes to marry the flavours. The sauce is ready when it coats the back of a spoon in a deep, even garnet layer.
4. 4
   Remove the pan from direct heat. Add the cold butter cubes one at a time, swirling the pan continuously to emulsify each piece before adding the next. Finish with a small squeeze of lemon juice and the finely chopped flat-leaf parsley. The sauce is ready when it is glossy, cohesive, and coats a spoon without breaking.
5. 5
   Taste and adjust seasoning. If residual tannin persists, add a half-teaspoon of redcurrant jelly and stir to dissolve. For a smooth result, pass through a chinois; for the traditional rustic version, serve with the melted shallot retained. The sauce is correctly seasoned when wine, fat, and fond are indistinguishable from one another.