Scrub, trim and halve radishes (quarter if very large). Peel whole garlic cloves. In a large bowl, toss vegetables together with olive oil and season with salt and pepper to taste.
Spread vegetables on a baking sheet, ensuring radishes have their cut sides down on the surface to encourage browning.
Bake at 350 for 25-30 minutes, or until the cut side of the radishes are golden brown and a knife blade slides easily through the center of a radish. The skins will wrinkle and take on a golden hue.