Silky and soft, these are the ultimate comforting mashed potatoes. Caramelized leeks and nutritional yeast give these vegan spuds even more richness and complexity than butter and cream. Use a golden-colored (not brown) vegetable broth to keep the potatoes a pale hue. A ricer or food mill will yield the creamiest mashed potatoes, but you can mash them by hand with a large fork too — you’ll just end up with chunkier spuds.
Creamy Leek Mashed Potatoes
Put the potatoes in a large saucepot and add enough cold water to cover by 2 inches. Add 3 tablespoons salt. Cover and bring to a boil over high heat. Reduce the heat to keep the potatoes boiling without causing the water to spill out. Continue cooking until the potatoes are very tender, about 15 minutes. A knife should slide through very easily and cause the potato to split.
While the potatoes boil, combine both oils, the leeks and a generous pinch of salt in a large saucepan. Set over medium heat and cook, stirring occasionally, until the leeks are very tender, about 15 minutes. Add the nutritional yeast and cook, stirring for 1 minute, then add the broth. Bring to a boil, then simmer for 10 minutes.
Drain the potatoes and let stand in the colander until very dry, about 5 minutes. Pass the potatoes through a food mill or ricer back into the pot in which they cooked.
Transfer the leek mixture to a blender and puree on high speed until very smooth. Add 2 cups of the leek mixture to the potatoes and fold gently until evenly distributed. Season to taste with salt and pepper. For creamier potatoes, fold in more of the leek mixture. Transfer to a serving dish, drizzle with more olive oil and garnish with chives.