How to Make It
Preheat oven to 475°F. Toss together carrots, turnips, potatoes, onions, oil, and salt in a large bowl. Divide mixture evenly between 2 baking sheets, spreading in a single layer on each. Bake in preheated oven until vegetables are lightly charred and tender, 25 to 30 minutes, switching pans top rack to bottom rack halfway through baking. Serve vegetables with warm Bagna Cauda for dipping.
Stir together garlic cloves, anchovy fillets, olive oil, oregano sprig, and salt in a saucepan over medium-low; cook, stirring occasionally, 5 minutes. Remove oregano sprig; whisk in butter. Serve sauce warm.