I love crostata, it is one of those things that make you smile when you get up early in the week. The taste of the jam and the butter tart with a scent of lemon are the best match. Not mentioning that it made me win a baking competition in my last job 😉
You can use any jam you like, I had one home-made, but I would advice to use a blackberries or raspberries one. They taste lovely with the lemony base of it. If you do not have lemon, try with some orange zest, or with both, and tell me how your taste buds react!