Boiling potatoes whole and unpeeled means they don't absorb too much water as they cook. Mixing them with an egg yolk and olive oil yields a rich dressing without the heavy creaminess of mayonnaise.
3 lb. Yukon gold potatoes
2 tsp. kosher salt, plus more to taste
2 1⁄2 tbsp. fresh lemon juice
1 small red onion, thinly sliced, soaked in ice water 10 minutes, and drained
1⁄2 cup canola oil
1⁄4 cup extra-virgin olive oil
1 egg yolk
2 tbsp. marjoram leaves
1⁄4 tsp. sweet paprika
Boil potatoes in a 6-qt. saucepan of salted water. Reduce heat to medium-high; simmer until potatoes are tender, about 25 minutes.
Drain potatoes and transfer to a bowl;. when cool enough to handle, peel potatoes and coarsely mash. Toss 2 tsp. salt, the lemon juice, and onion in a separate bowl; set aside. Whisk oils and egg
yolk in another bowl until combined; add to potatoes and toss to combine. Transfer potatoes to a serving platter and top with reserved onions; sprinkle with marjoram and paprika.