Preheat the oven to 350 and line a baking sheet with parchment paper.
Core the quinces and cut into uniform pieces, no bigger than 1 inch. (Most people peel quinces for a completely soft, even texture, but I didn’t and they turned out lovely with slightly crisp edges on a few of them. It was also much faster to prepare them.) Spread the quince in a baking dish (not the lined baking sheet) in an even layer.
Combine the sugar, maple syrup, cinnamon stick, cloves, and allspice in a medium pot and bring to a boil, stirring to dissolve the sugar.
Pour the liquid over the quinces and put the baking dish in the oven.
Bake for about 3 hours, stirring the quinces after 30 minutes to make sure they are evenly coated in syrup, and then again every 45 minutes to make sure they do not burn.
The quinces will be done when they turn a gorgeous ruby red, and the syrup has completely evaporated.
Remove the dish from the oven and transfer the quince pieces to the parchment paper to cool.
Now you have choices. You can either toss the quince pieces in confectioners sugar and serve them as candies (the sugar will melt on the quince if stored for too long). You can serve them as they are or blend them into a paste (much like guava paste) to devour alongside a platter of cheese. Or, chop them into smaller pieces and to bake with them or top granola!
To lighten the sticky mess and dishes, I like to use a Silpat, a non-stick silicone baking mat. Parchment paper works too!