Weigh out all ingredients and keep them ready
In a saucepan, whisk together milk, cream, sugar, and cornflour
Heat on medium heat, whisking continuously, until the mixture thickens slightly to a custard-like consistency
Pour the hot mixture over the chopped chocolate and let it sit for 30–60 seconds
Mix until the chocolate melts completely
Add cold cubed salted butter and vanilla extract, then mix until fully incorporated
Blend using a hand blender until the crémeux is perfectly smooth, glossy, and emulsified
Transfer to a container, cling wrap directly on the surface, and refrigerate for a few hours until fully set
