This yum-tiddly-umpum recipe for lemon curd makes three jars. You will need a slow cooker with a lid, three jam jars and a ceramic bowl or basin that will fit inside your slow cooker when your slow cooker has its lid on. You will also need tin foil to cover the top of the basin while it is in the slow cooker. The lemon curd will keep in the fridge for up to four weeks.