Step 1

Place 2 lb. baby Yukon Gold potatoes in a large pot, cover with 3 qt. water, then 1 cup kosher salt, and bring to a boil over medium-high heat. (Yes, this is a lot of salt, but it’s the right amount for the job. Potatoes are big and dense—so it takes highly concentrated water to ensure they're seasoned through and through, Plus, think about how much of that gets left behind in the water you pour out!) Once water comes to a boil, reduce heat, adjusting as needed to maintain a simmer, and cook potatoes until fork-tender, 15–20 minutes.

Step 2

Meanwhile, make your dressing. Combine ¾ cup sour cream, ¼ cup mayonnaise, 1 Tbsp. onion powder, 2 tsp. Dijon mustard, and 1 tsp. black pepper in a large bowl. Finely grate 1 garlic clove into dressing and stir to combine. Thinly slice 1 bunch chives. Transfer half of chives to dressing; set remaining aside for serving. Slice ¼ small red onion as thinly as possible through root end. (This might not be the way you usually cut an onion, but we're going for shallow arcs rather than chunky quarter-moons.) Transfer to a fine-mesh sieve and rinse for several seconds (this eliminates some of that astringent raw onion flavor). Pat dry with paper towels. Add half of onion to bowl with dressing; reserve remaining onion for serving.

Step 3

When potatoes are tender, scoop out ½ cup potato cooking liquid—we're going to use this later to thicken the sauce, warm up the cold dairy, and flavor the potatoes. Drain potatoes in a colander and let cool 10 minutes or until cool enough to handle. Crush each potato slightly with your hands (it's easiest to do this if you transfer them to a baking sheet or big plate first) and add to bowl with dressing.

Step 4

Toss potatoes with dressing and ¼ cup potato cooking liquid. You want to do this while the potatoes are still warm so that they'll better absorb all of the seasoning. Don't worry if the dressing looks a little loose and watery at the beginning—it will all get absorbed and be nice and creamy. Taste and add more salt or, if your dressing looks too thick, a splash of potato cooking liquid.

Step 5

Top potatoes with reserved chives and onion. Crumble ½ cup sour cream and onion potato chips over—in big pieces if you really just want to be eating a bag of chips or in small pieces if you'd like more of a bread crumb effect.