One place I used to work at made it with 5-pound jars of peeled garlic cloves, usually a total of 15 or 20 pounds at a time. Put the garlic in a 2-inch-deep hotel pan, pour in olive oil (1/2 cup for every 5 pounds of garlic), mix thoroughly to cover all the cloves, cover tightly with foil, and bake about 45 minutes in a 325-degree convection oven. Rotate the pan(s) once during baking. When the cloves are golden, it's done. We would then puree it, but you needn't if you want to use the cloves whole.
You could probably add sprigs of whatever herb you wanted -- although I thing fresh thyme would be best. If you want basil, try using a spinkle of dried; fresh might be too delicate.