Burnt Onion Butter

Ingredients

• 1 tablespoon vegetable oil
• 1 small red onion, ½ finely chopped, ½ thinly sliced
• Kosher salt and freshly ground black pepper
• ½ cup (1 stick) unsalted butter, room temperature
• A 4-oz. ramekin; spice mill or mortar and pestle

Steps

1. Heat oil in a medium skillet over medium heat. Add chopped onion; season with salt and pepper and cook, stirring occasionally and adding 1 Tbsp. water to skillet if onion on bottom is getting too dark, until deeply browned and very soft, 20–25 minutes. Let cool.
2. Mix butter and caramelized onion in a medium bowl; season with salt, transfer to ramekin and smooth top.
3. Meanwhile, heat broiler. Broil sliced onion in a single layer on a broiler-proof baking sheet, turning occasionally, until dry and completely blackened, 12–15 minutes. Let cool, then grind to a powder in a spice mill or with a mortar and pestle.
4. Dust butter with burnt onion powder.
5. DO AHEAD: Onion butter (without onion powder) can be made 2 days ahead. Cover and chill. Sprinkle with onion powder just before serving.