Combine ¼ cup milk with the cornstarch in a small bowl and whisk until smooth.

Whisk the egg yolks in a separate heat-proof bowl.

Combine the remaining milk with the sugar and salt in a medium saucepan and heat over medium heat. Heat just until the milk starts to steam, do not let boil.

Once the milk starts to steam, slowly whisk in about ½ cup into the eggs, whisking constantly. Slowly add the milk/egg mixture back into the pot and then add the cornstarch mixture. Cook the mixture over medium heat, whisking constantly, until the mixture thickens. Take off the heat and whisk in the butter and vanilla.

Pour the mixture into 6 individual serving bowls, place a piece of plastic wrap directly on the surface of the pudding to prevent a skin from forming, let cool, then refrigerate for several hours or until chilled and firm.

Top as desired and serve.