Makes 8 servings
- 3 lbs. fingerling potatoes, halved crosswise if large
- 1/2 c. olive oil, divided
- Kosher salt, freshly ground pepper
- 1/4 c. Sherry vinegar or red wine vinegar
- 1 tbs. whole grain mustard
- 1 jalapeño, thinly sliced, seeds removed (I diced it finely)
- 1/4 c. (lightly packed) chopped flat-leaf parsley leaves
Preheat oven to 450. Toss potatoes with 1/4 c. oil on a rimmed baking sheet: season with salt and pepper. Roast, tossing once, until golden brown and tender, 30-40 minutes. Let cool slightly, then lightly flatten.
Meanwhile, whisk vinegar and mustard in a large bowl. Gradually whisk in remaining cup of oil until emulsified; season with salt and pepper. Add potatoes, jalapeño, and parsley and toss; season with salt and pepper.