Single-serving cheesecakes made in glass jars are adorable and easy mini alternatives to their full-size cousins. They bake in just half an hour and can be cooked a few days ahead of time; layers of preserves and crumb topping can be added shortly before sealing or serving to prevent sogginess. Whip these up for your own party, or label with tags and carry to a potluck--their lids make them transport-ready. The best part? No messy slices -- just dive in with a spoon!