Membrillo is a Spanish confection, popular in much of western Europe under various names. It’s a thick gel made basically from equal parts of quince puree and sugar. It’s sweet and tangy. I’ve found it in the international sections of Shoppers Food Warehouses.
Manchego is a Spanish cheese that comes from, and is named after, La Mancha. Yes, it is it Manchego the cheese of La Mancha. It’s semi-soft, creamy, and just a fantastically delicious cheese. I’ve found it in the cheese bars at Harris Teeter.
If you cut the manchego into triangles and the membrillo into small cubes, serve them on a toast point and they make a superb tapa. Slice up the manchego and melt the membrillo into a spread with a little water and a lot of whisking, and they can be combined into a grilled cheese sandwich you would not believe. They are so fantastic together, it more than makes up that I’ve never seen both in the same grocery store.