Tarte à la bouillie are a simple egg and milk custard tart associated with the Cajun cuisine of southern Louisiana. It is made with a thick, sugar cookie-like crust and a filling made from a cooked custard of milk, cream, eggs, sugar, and flour, often flavored with vanilla.
The term “bouillie” refers to a pudding or vanilla custard; do not confuse it with bouillir, "to boil," which is from French.