Beurre de Baratte is a process used in French dairies to make a certain type of butter.
Milk is “soured” with bacterial starter cultures. This develops the flavour, thickens the cream and the butter globules begin forming.
The buttermilk is then spun off, and the butter globules are creamed with a churning machine, rather than with a centrifugal method continuous churn. Some manufacturers separate the milk from the cream at the start, keep the cream, add more cream on top, then start making the butter.
Despite the name (“baratte” means “churn”), and despite some people describing it as being made in a “classic churn”, the commercial butter sold is not actually churned by hand in a wooden churn. It’s a modern machine that does it. A few very small producers still make artisanal “Beurre de Baratte”, working it by hand with two small wooden paddles, but the output is not high, as can be imagined.
Beurre de Baratte is a bit more expensive than other butters, and is still subject to all other French butter regulations — e.g. can’t be more than 16% water, etc. Colouring can still be used.
Some people complain that Beurre de Baratte isn’t actually as practical or useful as centrifugally-made butter. In the making of butter centrifugally, all the whey gets driven off. The churn method, however, isn’t as efficient at getting rid of whey, which can make the butter somewhat “soggy” in comparison, and go rancid faster.