Ingredients  
1 cauliflower 
120ml white wine 
50ml white wine vinegar 
½ tbsp shallots 
225g diced butter plus 25g for cooking the cauliflower 
Oil 
100ml boiling water from the kettle.

Method  
You want to cut 2 ‘steaks’ out of the centre of the cauliflower.  To do this, take off all of the outer leaves and cut the base so it is straight and stands easily.  You want a thick steak so working from the centre, measure out an inch or so and cut straight down to the bottom.  Go back to your centre line and again cut straight down. You should now have a ‘steak’.  Repeat on the other side so you have two ‘steaks’.  Keep the remaining cauliflower for another recipe. 

Brush oil over the cauliflower, heat a frying pan and when hot add the ‘steaks’. Cook for a few minutes without disturbing, you want the cauliflower to nicely caramelise.  Once it looks golden, turn and repeat.  Once golden turn again and add the butter, turn again after a minute add the water and put on a lid and leave for a few minutes before turning again.  You want the ‘steak’ to be tender and the liquid to be evaporated. 

Fill the thermos with boiling water.  

While the ‘steaks’ are cooking, bring the wine, vinegar and shallots to the boil and reduce until you have 1 tbsp of liquid. Strain and return to the heat. Add the butter one cube at a time whisking constantly until you have 2 pieces left. It should be thick and glossy. Add the remaining butter off the heat, empty the flask and put the sauce into the flask.  This will keep the sauce warm while you finish off the dish.