Combine milk and buttermilk in a large bowl. If using rennet tablet, mix it with about a tablespoon of warm water to dissolve first, and add to the bowl. Cover the bowl with plastic wrap and allow to stand at cool room temperature for 24 hours.
The next day, the milk should have separated. Place a large sieve over a wide bowl, and pour the clabbered milk into the sieve. Wrap plastic wrap over the whole thing and let it continue to stand and drip for another day.
On the third day, pour off the liquid from the bowl and move the sieve and its contents onto a clean bowl or pan. There won't be as much liquid now, so it doesn't have to be as large as the first bowl. Cover again and store in the refrigerator for one more day.
On the fourth day, the Creole cream cheese is ready to be packaged in plastic containers or eaten. It can also be frozen. The classic way to eat it is doused with a little light cream or half-and-half, with sugar to taste.