How to Make High-Protein Mashed Potatoes

Method

1. 1

   Boil the potatoes whole. Scrub the Yukon Golds and boil them whole, skins on, in well-salted water until a knife slides through with no resistance — about 20 to 25 minutes depending on size. Cooking them whole rather than cubed keeps water out of the flesh, which matters here: you are about to add a protein that absorbs liquid, so you want the potatoes themselves as dry as possible. Drain thoroughly and let them steam in the colander for two minutes.

2. 2

   Hydrate the protein in the milk. While the potatoes drain, whisk the potato protein isolate into the warm milk in a separate jug until smooth. This is the step people skip and regret. Isolate is finer than flour and will clump if it hits hot starch directly, leaving chalky pockets in the finished mash. Whisking it into warm — not boiling — milk first lets each particle hydrate evenly, and the mixture will thicken slightly as it sits. Add the butter to the warm milk so it melts through.

3. 3

   Peel and rice the potatoes. Once the potatoes are cool enough to handle but still hot, slip the skins off and press the flesh through a ricer or food mill into a wide bowl. A ricer matters more than usual with added protein, because mashing by hand tempts you to overwork the potatoes, and overworking releases starch that turns mash gluey — a texture the extra protein will only exaggerate. Riced potato falls in light, dry strands that fold easily.

4. 4

   Fold in the milk mixture. Pour the protein-milk slowly into the riced potatoes, folding with a spatula rather than beating. Add it in two or three additions and stop as soon as the mash looks creamy and holds a soft peak — the protein continues to absorb liquid for a minute after mixing, so a mash that looks slightly loose will firm up. If it tightens too much, loosen it with a splash more warm milk. Season with the salt and pepper, taste, and serve immediately while the texture is at its best.