There are a few possible reasons why your jam cake may be dry: 1. Overbaking. Baking the cake for too long, or at too high a temperature, can lead to dryness. Follow the recommended baking time and temperature specified in the recipe. Every oven is different, so it's important to check for doneness using a toothpick inserted into the center of the cake. If it comes out clean or with a few moist crumbs, the cake is done. 2. Incorrect ingredient measurements. Baking is a precise science, and even small variations in ingredient quantities can affect the final texture. If you accidentally added too much flour or not enough liquid, it can result in a dry cake. 3. Lack of moisture. Jam cakes typically rely on the moisture from the jam to keep them moist. If the jam used is not sufficiently moist, or if you used too little jam, it can contribute to dryness. 4. Overmixing. Overmixing the batter can lead to the development of gluten, resulting in a dense and dry cake. Mix the ingredients just until combined.