Preheat your oven to 200°C (400°F). Gather your baking sheet, mixing bowl, small knife, and spoon to prepare for roasting.
Trim the radish greens and cut the radishes in half if they are large, or leave small radishes whole for a more delicate bite.
Peel and roughly chop or smash the garlic cloves to release their fragrant aroma.
In the mixing bowl, toss the radishes with olive oil, salt, black pepper, and the prepared garlic until everything is evenly coated and glistening.
Spread the coated radishes on the baking sheet in a single layer, cut side down if halved, to promote even caramelization.
Place the baking sheet in the oven and roast for 20 to 25 minutes, checking at the 15-minute mark. The radishes should be golden, blistered, and tender, with the garlic turning fragrant and soft.
Once done, remove the tray from the oven and squeeze fresh lemon juice over the radishes to brighten their smoky sweetness.
Gently toss the radishes with the pan juices and roasted garlic, then transfer to a serving dish.
Serve the roasted garlic radishes warm as a flavorful side, enjoying their tender, caramelized texture and fragrant aroma.