How to Make It
Preheat the oven to 425°. In a large bowl, toss the parsnips with 1/3 cup of the olive oil and season with salt and pepper. Spread the parsnips on a large baking sheet in an even layer and roast for 30 minutes, until caramelized.
In a small bowl, whisk the vinegar, mustard and sugar with the remaining 1/3 cup of olive oil until blended. Stir in the parsley, season with salt and pepper and pass the vinaigrette alongside the roasted parsnips.