you can do this with pre-made french bread if you're short on time but i really think it's worth it to do this from start to finish on a lazy afternoon. goes beautifully with pasta or a nice light cream soup. i use my own homemade butter for this (possibly because i'm crazy). if you want to do that it's really easy: just take whipping cream at room temp, whip it way past the point of whipping cream and you'll see the fat separate from the milk. squeeze the newborn butter to the side of the bowl and pour off the milk (keep that, it's perfectly good), rinse the butter under cold water three or four times, breaking it up to wash out the extra milk, then mix in a little salt.
you can easily double or triple this but it may or may not freeze well. the dough and butter would probably freeze better separately.