This is my version of what I recognise to be the best potato purée I have ever tasted - it's the Clasic French purée made by Chef Joël Robuchon who dedicated an entire book to potatoes. His secret - lots of fresh cold butter and stirring vigorously the puré. In calorie terms it's more or less the same as french fries so don't panic when you see the amount of butter that goes in it. You need to know 2 things to get a good potato purée: First it's the quality of your potatoes. Choose yellow starchy potatoes like Yokon Gold for a creamy and smooth mash as they have more moisture. The second tip is to never ever process your potatoes. Use a potato ricer or an old fashioned hand held food mill (ex. Oxo Good Grips Food Mill). Both these options purée the potatoes without making them gluey. If you process your potatoes with a hand held immersion blender or a food processor the processing releases more gluten and makes your purée like glue. This said, the recipe follows very closely Robuchon's recipe but I made a few adjustments - I have a real hard time following recipes exactly as they come in a book! —Maria Teresa Jorge
Wash the potatoes very well and cut them in half horizontally. The potato halves should be very similar in size so they cook evenly. Put them in a large enough pot and cover with cold water, about 1 inch of water above the potatoes. Add 1/2 tablespoon of coarse salt for every 1 quarter of water in the pan.
Once the water reaches boiling point, lower the heat to low medium and simmer the potatoes uncovered for about 20 minutes or until the blade of a knife inserted in the potato goes easily through it.
Work quickly with the potatoes still hot - Drain the potatoes, put half a potato in your potato ricer using the disk with smaller wholes, potato skin side up. Press the potato into a pan, release the handles, open and remove the skin left inside. Continue with the remaining potatoes. If using a food mill, peel the potatoes before milling them.
Put the pan over medium heat and stir vigourously for 4 minutes with a wooden spatula, letting any excess water evaporate. Start adding the small pieces of cold butter, little by little, incorporating very well and stirring vigourously (no need to go to the gym tonight!). Again, don't stress over the amount of butter, it's still less caloric then french fries and once you try theis purée you will taste the difference.
Bring the milk and the cream to a boil and add in a stream to the potato mix, until completely absorbed. Depending on the moisture level of your potatoes you might need to adjust the quantity of milk, you don't want a solid purée nor a runny one. So go slowly at the end to make sure you get the right consistency. If you need to add more milk, make sure you add it hot.
Check the seasoning - salt only. This classic French purée does not have pepper, nutmeg or any herbs added to it.
Put the purée in a bain-marie to keep warm, adding a little butter over the purée so it doesn't form a dry skin.
Serve the purée as a side dish for fish like sole meunière, chicken and braised meat.