Custard powder is a starch that is colored and flavored -- in vanilla, chocolate or fruit varieties -- so that when hot liquid is introduced, it turns into a custard-like product. It has a distinct, starchy aftertaste that isn't to everyone's liking. While custard powder is readily available in the United Kingdom, it is harder to find in the United States. Several products can stand in as substitutes for dessert recipes that call for custard powder.
Pudding Mix
Substitute instant vanilla pudding mix custard powder in pudding, sauces, baked goods and fillings. Use instant vanilla powder in equal parts to vanilla custard powder. Or substitute plain pudding or chocolate pudding mix in equal parts to vanilla custard powder.
Cornstarch
Because custard powder contains mostly cornstarch, you can make your own starchy thickener at home. Use equal parts cornstarch for custard powder and add enough vanilla extract for taste. Use cornstarch in place of custard powder in cakes, sauces, desserts and for quick puddings.
Pastry Cream
Pastry cream is a custard made from milk, eggs, sugar and cornstarch. Use homemade pastry cream in place of vanilla custard powder for puddings and fillings. Incorporate vanilla extract or real vanilla beans in the pastry cream to get vanilla flavor. A pastry cream is cooked on the stove, then cooled.
Tapioca Powder
Instant tapioca powder is a silky powder with a similar consistency to cornstarch. It is a natural thickener and can be used in place of custard powder. Use tapioca powder and vanilla extract in place of custard powder for cakes, fillings and baked goods. Use equal parts tapioca powder to custard powder and enough vanilla extract to taste. Don't confuse tapioca powder with tapioca pearls. Pearls require soaking before use and are primarily used to make tapioca pudding.