How to create Soft jam drops please

If you could clarify exactly what happened, with a link to the recipe, it would be helpful. In the meantime, this recipe substitutes cornstarch for some of the flour to make them softer; perhaps you could try that next time: https://lifemadesweeter.com/shortbread-thumbprint-cookies-7-ways/ . As far as the cookies you have already baked, not much you can do to change them, perhaps they will be softer the day after baking. Did they overbake and turn brown on the bottom? Was there a problem with the oven temperature (you can check the temperature with an oven thermometer)? Were they left in the oven too long?