Gather all ingredients.

Place milk, vanilla extract, and butter in a saucepan.

Cook and stir over medium heat until simmering; remove from heat before it comes to a boil.

Whisk eggs, sugar, and cornstarch together in a bowl until sugar dissolves.

Set the saucepan back over low heat. Pour in egg mixture slowly, whisking constantly, until custard thickens enough to coat the bottom of a spoon, 5 to 10 minutes.

Serve warm or transfer custard into a large bowl and cover.

Allow to cool before chilling. Enjoy!