It was a jam that my sister served during summer breakfast. Visiting her in Switzerland, the German label intrigued me. It read "quince and pumpkin marmalade." Curious about the flavors, I dunked my knife in and spread it on some bread. It was good. Very good. So back at home in sunny Sunnyside (Queens, NY), I put my hand to making a batch in my kitchen. With no actual recipe, I took hints from David Lebowitz's version of a pumpkin marmalade. Only I substituted butternut squash for pumpkin. Know what? It tasted close to that lovely summer Switzerland breakfast with my sister. Good.