Cut the top of the head of garlic off to expose all the cloves. Rub the 1 tsp of oil into the garlic.
Place two pieces of tinfoil on top of each other (shiny side in) and place the garlic inside. Wrap tightly to make a little packet and bake until soft and tender and easily pierced with a fork, about 40-50 minutes.
Once roasted, squeeze all the cloves of garlic into a high-powered blender (or do just a few at a time if you don’t want as much garlic) and then add all the remaining ingredients.
Blend on high speed for about 30 seconds until smooth and creamy.
Transfer to an air-tight container and refrigerate for at least 2 hours to develop flavors.