This recipe is adapted from SimplyRecipes. I have made both her membrillo and her quince jelly, but here I’ve morphed the two. The instructions look long, but I assure you the process is super easy. The tl/dr version: Wash/core/chop fruit. Put fruit in a pot with water and boil until soft. Mash. Strain. Combine juice in a pot with sugar, vanilla bean, lemon zest, and lemon juice and boil for a while. Heat jars. Put hot jelly in hot jars. Put lids on jars. Done! Serve quince jelly on toast, croissants, popovers, and other breakfast pastries. It's also delicious as a condiment on a cheese plate, paired with salty blue cheese or manchego. You can even heat it up and use it as a glaze for a fruit tart or a sauce for poached fruit or ice cream. If you don't have quince, you could substitute pears, but you'll likely need to add pectin since pears don't have as much pectin naturally as quince do.