Preheat your oven to 400°F (200°C). Toss the prepared carrots, fennel slices, and red onion wedges in a mixing bowl with olive oil, salt, and pepper until evenly coated.
Spread the vegetables in a single layer on a baking sheet, ensuring they have some space between each piece for even roasting.
Roast in the oven for about 30-35 minutes, until the edges are slightly charred and caramelized, and the vegetables are tender when pierced with a fork.
Remove from the oven and let the vegetables cool for a few minutes. They should be soft with some edges catching a little char for visual appeal.
Transfer the roasted vegetables to a serving platter, arranging them nicely so their colors and textures are visible.
Sprinkle the freshly chopped mint generously over the warm vegetables to add a burst of color and brightness.
Finish with a light drizzle of olive oil for extra shine and richness.
Serve immediately, letting the flavors mingle and the aromas fill the room, capturing the warm, sweet, and herbaceous notes of this roasted vegetable medley.