The curd will thicken during cooking, but will continue to achieve a more spreadable consistency as it cools. Also, remember that the number of eggs you use can affect the thickness of your curd. If you want a thicker curd, use an extra egg or reduce the amount of lemon juice slightly. Conversely, if you prefer a lighter texture, use fewer eggs or more lemon juice. Adjust to your personal preference for the perfect lemon curd.