Ingredients
1 tablespoon vegetable oil
1 onion, finely diced
4 cloves garlic, minced
1/2 teaspoon salt
1/2 teaspoon pepper
1 pinch cayenne pepper
8 cups chopped swiss chard, without stems (about 2 bunches, 10 stalks)
6 to 8 black radishes, very thinly sliced
1/4 cup butter, melted
Kosher salt and freshly ground black pepper
Directions
In 10-inch nonstick ovenproof skillet (cast iron works great), heat oil over medium heat. Cook onion until softened, about 6 minutes, then add the garlic and sauté for an additional 30 seconds. Add salt, pepper and cayenne. Add chard in big handfuls, stirring constantly and waiting until each batch is wilted before adding more (about 1 minute between each addition). Once all the chard has been added to the skillet, cook for about 3 minutes more, stirring occasionally. Transfer to a paper-towel lined plate to drain some of the excess liquid. Do not clean skillet.
Preheat oven to 425F.
Using mandoline or sharp knife, cut black radishes into paper thin slices. Spread one-third of the radish slices on the bottom of the skillet you used to cook the chard and onion mixture, overlapping each slice a bit to create a pattern. Sprinkle radishes with a pinch of kosher salt and freshly ground black pepper. Top with half of the chard mixture. Repeat layers once. Top with remaining radishes, pressing well to evenly distribute. Pour melted butter over top.
Bake for about 50 minutes or until radishes are tender when pierced with a knife. Let rest for 10 minutes before serving, or let cool to room temperature and serve that way.