I have a fairly basic question here, which I wonder about every year, and thought it would be good to get a definitive answer!\n\nI don't bake heavy fruit cakes very often, but I do make a Christmas cake most years, and use my trusty old recipe from a Sainsbury's cookbook dating from 1980. It's a standard Christmas cake recipe, uses a 23cm round tin (I'm actually using a 20cm square one this year as that's about the same area) and suggests cooking the cake at "Gas Mark 2, or 150C" for "3 to 4 hours". I've done this every year, and the cake turns out fine inside, although it usually looks overdone on the top.\n\nHowever, the test for when it's ready is supposed to be "when a skewer inserted in it comes out clean". I don't really know what that means - my cake is in the oven currently (I've set it to about 140C rather than 150C as it's fan-assisted) and it's been in for 90 minutes so far, so only about half way through cooking. However, the top looks done, it feels quite firm to the touch, and a skewer inserted in the centre of it comes out clean - but it can't possibly be ready after only 90 minutes. So how *do* you tell when it's ready?\n\nMy secondary question relating to this is as I'm the only one in my circle of friends who likes Christmas cake, I'd like to make a smaller one, but how do I adjust the cooking time accordingly for a smaller cake? In other words, if it takes 3-4 hours for a 23cm tin, if I used 40% of each quantity and a 15cm tin, presumably as it's a smaller tin, the cooking time would be reduced - but to what?\n\nYou can probably tell I only bake a cake like this once a year, as it's a pretty newbie question :)\n\nThanks in advance!