Roasted cipollini onions with chile-rosemary butter

Ingredients

• 1 pound cipollini onions
• 1 tablespoon olive oil
• 2 teaspoons chopped fresh rosemary
• Pinch or two of red pepper flakes
• Kosher salt
• 2 tablespoons butter

1. Preheat the oven to 400°. Meanwhile, peel the onions.
2. Pour the oil into a Lodge 10-inch cast iron skillet. Add the onions, sprinkle with the rosemary and red pepper, and season with salt to taste. Turn them over in the oil until thoroughly coated. Roast the onions until they’re tender, about 30 minutes, turning them over every 10 minutes so they roast evenly.
3. Set the skillet on the stove-top over medium heat, and add the butter. Cook, stirring every now and then, just until the butter starts to brown, 1 to 2 minutes. Serve with a little of the butter spooned over the top.