Follow the donut-making method I shared before.
For the creme patisserie, whisk eggs, cornstarch, salt, and sugar. Boil milk and vanilla in a nonstick pan, then slowly pour it into the egg mixture while whisking. Cook on low heat, stirring constantly until you have a custard-like consistency. Add butter, mix, strain, and let it cool for 15 minutes.
Transfer the creme patisserie into a piping bag with a Bismarck 230 tip. Fill the donuts with the custard until they feel heavy.
For the caramel, mix the ingredients in a nonstick pan on low heat. Let the sugar dissolve and caramelize to a deep golden color.
While the caramel is hot, dip one side of the donuts for a thin caramel coating. If it starts to harden, reheat until runny. The donuts will form a crispy coating as they cool.
Serve and enjoy your delightful Crème Brûlée donuts!