500ml reduced beef stock (start with 2 litres, and boil down)
2 tbsp butter
2 whole brown onion, thinly sliced
3 rashers streaky bacon thinly sliced
2 cloves garlic, thinly sliced
200ml dry white wine
2 tsp wholegrain mustard
1 sprig of thyme
Crushed black pepper
Salt to taste
Lemon juice to taste
1tsp red wine vinegar
15g unsalted butter cut into cubes
Handful chopped parsley
Instructions
Fry the bacon in a little oil on a medium heat to render the fat. Remove the crispy bacon from the fat and add the onions to the pan, once they begin to soften, increase the heat and allow the onions to caramelise golden brown. Once golden, add in the thinly sliced garlic pieces, thyme and cook for a few more minutes.
Deglaze the pan with the white wine and reduce by at least half. Add black pepper. Stir well then add in the reduced stock and return the bacon to the pan.
Bring the sauce to a simmer and season with salt to taste. Leave simmering for roughly 2 minutes or until the sauce has thickened slightly. Stir in the mustard.
Add a squeeze of lemon, some Maldon salt, and red wine vinegar to taste.
Turn off the heat and add in your cold butter chunks from the fridge, moving the pan constantly to emulsify. Stir in your chopped parsley.
For a more rustic and chunky sauce, serve as is. If you want to refine it slightly you can strain the sauce through a fine mesh sieve using the back of a spoon to push through as much flavour as possible.
