Do as much as you want at a time because you can freeze what you don’t immediately need.
Put the whole garlic bulb (skin and all) into the oven at about 350°/180°. Slice the bottom off of the bulb.
Leave them in for about 20-30 minutes. Watch them carefully so they don’t burn! They will reach roasty goodness when the outer skins are browning.
Then, pop the cloves out of the husk.
Leave them to cool down, if you’re not using them right away.
I like doing a few bulbs at a time, so I can freeze some. To freeze, spread the cloves out on a baking sheet or anything flat that can fit into the freezer. Try to keep them from touching, so they can freeze as individual cloves instead of being glommed together.
Once they’re frozen you can store them in a container or a freezer bag.