Unlike a standard custard, a soft custard has a loose consistency resembling that of the so-called soft custard ice cream served on cones. This supple property makes a genuine soft custard ideal for filling pastries and topping desserts. The secret of making the preparation soft is to reduce the amount of binding that occurs between the egg protein molecules while you cook the custard. This requires stove-top (not oven) cooking because the mixture must be stirred constantly.