Whisk cornstarch, sugar, and salt together in a heavy-bottomed saucepan.

Add milk and egg replacer or banana and whisk until lumps disappear.

Heat over medium heat, whisking, until the custard thickens.

To test whether the custard is thick enough, dip a wooden spoon into the mixture and run your finger through the coating.

When the custard is thick enough, the trail will not close back up.

Take the custard off heat. Whisk in butter, vanilla, and nutmeg.

Cool with a plastic sheet pressed to the surface to prevent a skin from forming.

Bon Appetit!