AS a rule of thumb potatoes for mash are usually not potatoes for steaming or boiling. You want something that collapses. You can treat new potatoes as if they were a mash but you end up with a compromise we call crashed, which is fine but it is not what most people think of as a smooth mash. The whole point of mash is to slip some liquid or in there be that butter, milk, cream or olive oil or even a combo of all of them. or another vegetable.
Good mash varieties are Golden Wonder, King Edward, Wilja and Maris Piper.
If you are still thinking calorifically as it were, a 200g portion of steamed potato mashed with 20g of butter, or a ratio of 10%, roughly equals 140 calories. So relax, Not that fattening.
Add in 50mls or so of hot milk, whisking hard for seriously fluffy.
Some people hold that the potatoes are better baked which is a good trick if you plan ahead and can leave one ready in the fridge for tomorrow. Skin and revive the potato with butter, hot milk = dinner in 30 seconds.
The seasonings for mash are essentially alkaline anyway so be generous with salt, black pepper, nutmeg, cayenne, parsley, zest of lemon. The obvious herbs, parsley, mint, chives all work and used in quantity, say at least a tablespoon when diced and lend a new accent. You might go further still towards the Levant – boil the potatoes with onion, mash with a little oil and butter and milk then scatter in pine nuts, ground cinnamon, a tablespoon of fresh parsley, and a pinch of both nutmeg and chilli.
Of course, the great thing about mash is that it does not simply have to be a potato dish. Many combinations have been elevated to the cult status with their own names. You can choose either to boil both together, or separately.
Champ = mash with spring onions
Colcannon = with cabbage and onion
Punch-neo = with turnips
Most common although it does not seem to have picked up a moniker of its own is celeriac with half as much potato, some garlic (which is alkaline anyway). There are also half and half variations with parsnips. With most of these root vegetables you may want to up the calories with a little double cream. Or just add a few cloves of garlic with the potatoes for an edge…