Step 1

Place potatoes in a large pot and cover with water; season generously with salt. Bring to a boil over medium-high. Reduce heat to medium; cook until potatoes are tender when pierced with a fork, 16 to 18 minutes (be careful not to overcook). Drain and rinse under cold water. Let cool for 5 minutes. Cut potatoes in half crosswise, or quarter if large.

Step 2

Meanwhile, finely chop white and light green parts of scallions (you should have about ⅓ cup). Thinly slice dark green parts (you should have about ½ cup). Cook oil and garlic in a small skillet over medium low, stirring often, until garlic is golden, 6 to 8 minutes. Transfer garlic to a towel-lined plate with a slotted spoon; season with ¼ teaspoon salt. Add chopped white and light green parts of scallions to oil in skillet; cook over medium, stirring often, until softened, about 1 minute. Remove from heat. Transfer scallion-oil mixture to a large bowl. Let cool for about 10 minutes.

Step 3

Whisk vinegar, mustard, pepper, and remaining 2½ teaspoons salt into scallion-oil mixture until thickened and well-combined. Add potatoes, parsley, basil, and sliced dark green parts of scallions. Gently fold to combine. Top with crispy garlic chips before serving.