OK, this is super-easy. Lemon rind and juice, sugar, eggs and unsalted butter. Not worth buying it – unless, of course, you can buy it anywhere, but here in Switzerland it’s hard to find. Just recently, I’ve seen it for the first time in one of our major supermarkets, but at a price.
So, here’s Delia Smith’s Lemon Curd. The online recipe differs a little to the one in the book as it has cornflour, but it’s basically the same.