Roast the bulb of garlic in the oven for 30 mins at 350F. I put it on a baking sheet and wrap it with foil paper.
Take it out of the oven and let it cool ~5 mins.
Optional but highly recommended , whip the butter in a stand mixer.
Extract the garlic from the peel and put the garlic in a bowl and mash it. Add the butter and mash it with the garlic.
At this point add minced parsley, salt to taste
This will keep in your fridge for 7-10 days but I prefer to just freeze it in an ice cube tray or small container. I then transfer them in a Ziploc bag and take one off when needed. Either thaw in the fridge or nuke it in the microwave for ~10 seconds.