Ensure that all equipment used is clean and dry to prevent any unwanted bacteria from affecting the curd's shelf life. The steeping time for the elderflowers can be adjusted to taste; longer steeping will result in a more pronounced elderflower flavor. For a richer curd, use brown butter instead of regular butter. If you don't have fresh elderflowers, you can use elderflower cordial. Reduce the sugar by the amount of sugar in the cordial.