Heston Blumenthal's perfect mash
Heston Blumenthal: "The technique here, i.e. cooking waxy potatoes at a very specific temperature, is designed to hold on to the starch in the potatoes and prevent it from leaking out and turning the potato gluey. The end product is the creamiest smoothest pommes purées ever. If you want to be extra decadent, go 50:50 potato to butter. Adding lime jelly cubes for a fresh burst of flavour is optional."
1kg waxy potatoes, peeled – reserve the peelings
240ml whole milk
250g unsalted butter, diced
For the lime jelly cubes (optional)
Juice and finely grated zest of 10 limes
50g white caster sugar
1 tbsp agar flakes
Bring a saucepan of unsalted water to 72ºC over a medium heat.
Cut the potatoes into equal-sized pieces, rinse for 5 minutes and put into the pan and bring the water temperature back up to 72ºC.
Hold the potatoes at this temperature for 30 minutes, removing the pan to adjusting the heat as necessary.
After 30 minutes, drain the cooked potatoes and rinse them under cold running water.
Bring a saucepan of fresh salted water to the boil and add the potatoes. Cook until extremely soft and falling apart.
Meanwhile, add the potato peelings to the milk, bring to a boil and remove from the heat. Allow to stand for 20 minutes before straining and discarding the peelings.
Drain the potatoes, return them to the pan over a very low heat to dry them out.
Put the potatoes through a ricer on to the butter in a bowl, and mix together, then put mixture through a fine sieve add the warmed infused milk and salt to taste.
Place some of the pommes purées on a plate and sprinkle with lime jelly cubes if using.
For the lime jelly cubes (if using)
Put the lime juice and zest into a saucepan and place over a medium heat. Add the sugar and bring to a simmer.
Whisk in the agar agar flakes and simmer for 4 minutes.
Blitz the mixture with a hand blender and pass through a sieve into a shallow container. Place in the fridge to fully set (this should take approximately 2 hours).
When ready to use, remove the jelly from the fridge and cut into 1cm cubes.