Oven Setup : Position a rack in the center of your oven and preheat to 425°F (220°C).
Prepare the Radishes : Rinse and thoroughly dry the radishes. Trim off the rootlets and stems. Halve or quarter any radishes larger than one inch so all pieces are roughly uniform in size for even cooking.
Season for Roasting : In the large mixing bowl, combine the prepared radishes, avocado oil, sea salt, and black pepper. Toss until the radishes are lightly and evenly coated.
High-Heat Roasting : Tumble the seasoned radishes onto the rimmed baking sheet and spread them into a single, even layer. Roast for 25 to 30 minutes, shaking the pan once at the halfway point. The radishes are done when they are easily pierced with a fork and show golden-brown patches.
Develop Nutty Butter Glaze : About 5 minutes before the radishes are finished roasting, place the butter in the small saucepan over medium heat. Let it melt, then continue to cook, swirling the pan frequently. The butter will foam and then subside, leaving behind browned milk solids. Once it smells nutty and is the color of amber, about 3 to 5 minutes, immediately remove it from the heat.
Dress and Serve : Transfer the hot roasted radishes into a clean serving bowl. Scrape the browned butter and all the toasted bits from the saucepan over the radishes. Add the fresh dill, chives, and lemon zest. Gently toss everything together until the radishes are beautifully glazed. Add a final pinch of sea salt to taste and serve warm.
