Preheat oven to 350 degrees F.
Place unpeeled garlic cloves in baking dish. Add 2 tablespoons olive oil and sprinkle with salt and pepper; toss to coat. Cover dish tightly with foil and bake until garlic is golden brown and tender, about 45 minutes. Cool.
Squeeze garlic between fingertips to release cloves. Transfer garlic cloves to blender. Add vinegar and rosemary and puree herb mixture until smooth.
With machine running, gradually add remaining 1 cup olive oil. Season to taste with salt and pepper. (Dipping oil can be prepared 1 day ahead. Cover and refrigerate. Let stand 15 minutes at room temperature and whisk before using.)