Preheat the oven to 450°F.
Trim the radishes of their greens and wash thoroughly, as they can be sandy.
Cut any radishes that are large in half or quarters.
Trim the carrots of their greens, if they are still attached. Scrub or peel the carrots, then cut them to roughly the same size as the radishes, about the size of baby carrots.
Place vegetables in a bowl.
Melt the ghee on the stovetop or a microwave.
Spoon half the ghee over the vegetables and sprinkle with salt and pepper. Toss to coat.
Pour the vegetables onto a rimmed baking sheet. Roast for 16 to 18 minutes, or until the bottom and edges of the vegetables are golden brown.
Move warm vegetables to a serving dish. Drizzle remaining melted ghee, lemon juice and parsley over vegetables.
Add additional salt and pepper to taste if necessary, then serve.