Put the parsnips, carrots, oil, salt, and pepper in a large bowl and stir to evenly coat.
Spread the veggies out onto your prepared baking sheet(s) in a single layer. Ideally, the veggies will be spaced out so that they aren’t touching one another.
Roast for 35 to 40 minutes, stirring every 15 minutes to help them cook evenly.
If using dried herbs, heat the buttery spread in a small pan over medium-low heat. Add the shallot, chives, and thyme, and sauté for just a minute. The shallot will soften a bit and the herbs will become fragrant. If using fresh herbs, you can jump straight to the next step.
When you remove the vegetables from the oven, while they are still hot, toss them with the buttery spread, shallots, and herbs to coat.
Store leftovers in airtight container in the refrigerator for up to 2 days.