Pull your butter from the fridge to soften while the garlic roasts. Preheat your oven to 350°F.
Start by peeling as much paper from the garlic as you can, leaving the cloves intact to the root.
Trim off the tip of every clove of garlic to expose the clove.
Place in a small oven safe dish like a ramekin* and drizzle on the oil. Use your hands to make sure the garlic bulb is completely coated.
Cover with foil and roast for 1 hour, or until cloves are browned and soft. Allow to cool slightly.
When bulb is cool enough to handle, squeeze each clove from the bulb into a small bowl and use the back of a spoon to smash into a creamy paste.
Add the butter and salt to the garlic and stir until completely blended.
Place butter on a sheet of parchment or wax paper and roll into a log. Twist off the ends and store in the fridge to let it solidify.
Serve as needed. Store up to a week in the fridge or freeze.
Notes
* I used a mini loaf pan, but a ramekin, muffin pan, or even just wrapping the garlic clove in foil works just fine for roasting. If not using a dish, place a baking sheet under the wrapped garlic to catch any potential oil leaks.