Nigella's Chocolate Chheesecake recipe calls for "custard powder". Exactly what is it and where do i buy it?
Custard powder is a British product that is added to hot milk to thicken it and make custard, as an alternative to using eggs. It was invented by a Victorian called Alfred Bird, in the mid 1830's, as his wife loved custard but was allergic to eggs. Bird's is the most popular brand, though many UK supermarkets will offer their own label version. The custard powder used in the recipe is the traditional type that comes in a can and you add to milk, and not the "instant custard" that comes in a packet and just requires the addition of boiling water.
You can buy Bird's custard powder in most UK supermarkets. Outside the UK many on-line retailers who sell Britsh products sell custard powder (such as British Delights in the US) and Amazon gourmet is another possible source. In some larger cities with ex-pat communities you may also find supermarkets which have special sections for British and other international foods and this is another potential source.
Custard powder is based on cornflour (cornstarch), with vanilla flavouring and annatto colouring added. So if you can't easily find custard powder then you can replace it in Nigella's Chocolate Cheesecake recipe (from Feast) with 1 tablespoon cornflour, 1 teaspoon vanilla extract and a tiny pinch of salt.