Mashed potato is one of the few dishes where the butter is doing almost nothing you cannot get another way. A classic recipe takes 100 g of butter and 150 ml of double cream into a kilo of potatoes — about 22 g of fat a serving — and most of what those two ingredients contribute is the sensation of smoothness, which turns out to be a question of technique far more than a question of fat.
This version lands at 2 g of fat a serving. It is smooth, it holds its shape on a fork, and it does not taste like a diet.
Why This Version Works
A potato is a bag of starch granules. When you cook it, those granules swell and separate; when you handle it badly, they burst and release free starch, which is what makes mash go gluey. Butter helps mask that, because fat coats the broken starch and dulls the stickiness. Take the butter out and you have nowhere to hide — which is why low-fat mash so often comes out like wallpaper paste.
So the fat gets replaced by three pieces of handling. First, a ricer rather than a masher or, heaven help you, a blender: a ricer pushes the potato through in strands without crushing the granules. A stick blender shears them open and produces something closer to glue every single time.
Second, dry the potatoes before anything goes in. One minute back in the hot empty pan evaporates the surface water, which means the potato takes the liquid you add rather than the liquid it is already carrying.
Third, warm the liquid and add it slowly. Cold dairy hitting hot starch tightens it, and the mash then needs more beating to come together — which is exactly the beating you are trying to avoid. Buttermilk is the choice here because it brings acidity and body for roughly 1 g of fat in the whole bowl, and the slight tang does a surprising amount of the work that butterfat usually does.
Roasted garlic covers the rest. Long slow roasting turns it sweet and almost creamy, and it gives the mash somewhere to go that is not simply “rich”.
Honest comparison: the butter-and-cream version runs about 22 g of fat a serving. This one runs 2 g.
Ingredients
- 1 kg floury potatoes (Maris Piper, King Edward or russet), peeled and cut into even 5 cm chunks
- 1 whole head of garlic
- 200 ml low-fat buttermilk, warmed
- 100 ml of the potato cooking water, or warm skimmed milk
- 2 tsp olive oil
- 1 tsp salt for the mash, plus salt for the pan
- white pepper
- 2 tbsp chopped chives
Serves 6.
Instructions
- Heat the oven to 200 °C / 400 °F. Slice the top off the head of garlic, wrap it in foil with half a teaspoon of water and roast for 35–40 minutes until the cloves are soft. This can be done days ahead.
- Put the potatoes into a pan of cold salted water, bring to the boil and simmer for 18–20 minutes, until a knife slides in with no resistance. Starting them in cold water matters: dropped into boiling water, the outsides turn to mush before the middles cook.
- Drain, keeping 100 ml of the water, and return the potatoes to the dry hot pan for one minute, shaking it, to drive off surface moisture.
- Pass the potatoes through a ricer or a food mill straight back into the pan. If you only have a masher, mash in the pan and stop as soon as the lumps are gone. Never use a food processor or a stick blender — see below.
- Squeeze in the roasted garlic cloves. Warm the buttermilk and reserved water together until steaming, not boiling, and pour in roughly a third at a time, folding with a spatula after each addition.
- Fold in the oil, the salt and a good grind of white pepper. Taste and adjust. Serve with the chives scattered over.
Nutrition
Fat: 2 g · Saturated fat: 0.4 g · Calories: 165 kcal · Protein: 5 g · Fibre: 3 g · Carbs: 32 g · Serves: 6 · Prep: 15 min · Cook: 30 min
Figures are per serving, one sixth of the bowl. Nearly all the fat is the two teaspoons of oil; the potatoes themselves carry a fraction of a gram. Leaving the oil out entirely brings it to under 1 g, though the mash reads a little flatter on the tongue.
Variations
- Celeriac: replace a third of the potato with celeriac. Fewer calories, more flavour, and it mashes beautifully.
- Horseradish: 2 tsp of grated horseradish folded in at the end, for serving with beef.
- Mustard and spring onion: a teaspoon of wholegrain mustard and a handful of sliced spring onions — closer to a champ.
- Dairy-free: use unsweetened oat milk with a teaspoon of lemon juice stirred in, warmed, in place of the buttermilk.
Storing and Reheating
It keeps for three days in the fridge. Reheat it gently in a pan with a splash of warm milk, stirring as little as you can manage, or covered in the oven at 170 °C. The microwave works but tends to dry the top, so cover it. Mash freezes for two months and comes back better than most people expect, provided you thaw it fully before reheating.
What to Serve It With
It sits under anything with a sauce: a lean braise, baked fish, a roast chicken breast. On a holiday table it goes next to stuffing and green beans without any of the three fighting for the same richness. If there is gravy, skim it properly — that is usually where the fat you just saved walks back onto the plate.
Questions People Ask
Why does my low-fat mash turn gluey?
Almost always over-working. Any blade appliance — food processor, stick blender, electric whisk — tears the starch granules open and releases free starch. Use a ricer, a food mill or a hand masher, and stop the moment the lumps are gone. Waxy potatoes are the other common cause; they hold together rather than falling apart, so they need more mashing to break down.
Which potatoes are best?
Floury ones: Maris Piper, King Edward, russet, Idaho. They have more starch and less water, so they absorb liquid cleanly and break down with little effort. Waxy varieties such as charlotte or new potatoes make a denser, stickier mash, and without butter that difference is very noticeable.
Can I make it without a ricer?
Yes. A hand masher is fine if the potatoes are floury and properly cooked. Push them through a coarse sieve with the back of a ladle if you want it very smooth. The one thing not to do is reach for a motor.
Can I make it ahead for a crowd?
Make it up to two hours ahead, cover it and hold it in a low oven at 90 °C, or over a pan of barely simmering water. Hold back a splash of the warm buttermilk and fold it in just before serving to loosen it again.
— Sophia
Written by
Sophia W. Whitman
Recipe developer and author of the Pancreatitis Diet Cookbook for Beginners. Cooking has been my life’s work, and low-fat cooking is the corner of it I know best. Every recipe here lists fat per serving, so you don’t have to guess.