Ingredients
1½ kg potatoes, cut into even chunks (I like Vivaldi but Maris Pipers or King Edwards will be good)
75ml double cream - you might not need it all
50g butter
Salt
Pinch of white pepper
Vegetable oil
4 x 150g cod fillets, skin on
2 tsps flour
300g asparagus
Salt
Black pepper

Ingredients for the beurre blanc
120ml white wine
50ml white wine vinegar
½ tbsp shallots
225g diced butter

Equipment Needed
Potato masher

Method
Put the potatoes into a large saucepan of cold water and bring to the boil.  Once the water is boiling, reduce the heat to a simmer and cook for about 15 minutes or until tender.

Meanwhile, boil the kettle, pour the water into a thermos and put on the lid.  This will heat up the thermos and keep it warm for the beurre blanc.

In a small pan, bring the wine, vinegar and shallots to the boil and reduce until you have 1 tbsp of liquid. Strain the liquid and return to the heat.

Lay the cod on some kitchen paper to remove any moisture so that the skin crisps up properly. Heat a frying pan on a medium high heat, add the oil, salt the skin and put ½ tsp flour on to it then put the fish in the pan, skin side down. As you put the fish in, carefully lay it and leave.  Don't move the pan or fish as you do not want to tear the skin. Cook the cod for 4-5 minutes without touching until you can see that the fish has started to go golden.  Turn the cod over and cook for a further 3-4 minutes.

While the cod is cooking, finish off the beurre blanc. Add the butter one cube at a time whisking constantly until all of the butter has gone. Drain the thermos and dry and put your beurre blanc into it to keep it warm while you finish off.

Grab a plastic carrier bag (an ordinary supermarket one will work), wash the inside, put your asparagus in and seal the bag ensuring there are no gaps for the steam to escape.  Don’t worry about drying the bag because it all helps with the steam. Put into the microwave on full steam for 2-3 minutes. If you have a steamer you can use this in place of the bag but it will take a little longer.

Transfer the potatoes to a colander and drain well, then return to the pan and set over a very low heat, start to mash your potatoes and continue mashing until really very smooth.  When you think it is smooth enough, mash some more, keeping the heat on low the whole time.

Put the butter into the potatoes and stir with a wooden spoon.  Start to put the cream in the potatoes, stirring with a wooden spoon, you might not need it all, just stop when you are happy with the consistency.  Check the seasoning and adapt if needed.  Put the lid on to keep it warm.

Very carefully undo the bag and check the asparagus are cooked to your liking.  Season with salt and freshly ground black pepper.

To serve, put a couple of spoonfuls of the mash on to the plate (to keep it very neat, use an upside down 4-5cm pastry ring), put the asparagus on the top and drizzle with the sauce. Top with the cod and serve with the remaining beurre blanc in a jug on the table.