The cactus is most likely a native to Mexico. It is has been noted that the Nopales was grown and eaten as a vegetable in Central Mexico, since before the Spanish arrived. The Spanish explorers took the plant back to Spain and the plant spread throughout North Africa with the Moors. The plant is currently grown throughout Mexico as well as parts of the United States and in many areas of the Mediterranean.
The plant is the genus Opuntia from the Cactaceae family, or what is commonly known as the Prickly Pear Cactus. Nopal means cactus in Spanish and Nopales is term for "cactus stem". The term Nopalitos refers to the pads once they are cut up and prepared for eating. There are two food crops derived from the prickly pear cactus. One is the "nopalitos" which are the cactus pads and the other crop is the prickly "pear" or fruit of the cactus.
Commercially two sizes of nopales pads are harvested which is small, (less than 10 cm long) or (medium less than 20 cm, about 100g). The Nopales leaf pads are usually harvested between spring and the end of summer. Select thin pads no longer than 20cm or 8 inches. Make sure to wear heavy gloves to harvest the pads yourself. The pad will snap off easily or you can use a large knife to sever the stem. Beware, there are large and fine thorns so be sure to keep your hands protected. To prepare the pads remove the thorns and the "eyes" with a vegetable peeler or a small paring knife or this new gadget designed just for spine removal. Wash the pads well with cool water and peel or trim off any blemished or discolored areas. Slice the pads in long slices or in pieces or leave whole depending on the dish you will prepare.
Nopales is a vegetable that can be eaten grilled or boiled. Over cooking may give them a slightly "slimy" texture you may want to avoid. Frequently the nopales are added to eggs, or as a vegetable in soups, chilies or a filling in a tortilla.
The best preparation we have tried is to prepare the nopal leaves (remove spines) then grill over hot coals till tender and slightly browned. Then slice into nopalitos strips and toss with a squeeze of lime and a little bit of olive oil. They are delicious. There is also a local restaurant that grills portobello mushrooms along with the nopales an slices both and serves them tossed together.
You may store fresh (not wrinkled) nopales refrigerated, tightly wrapped, for up to two weeks.
Nopalitos are normally found in cans or jars in any grocery store that sells Mexican foods. Fresh nopalitos are available in Mexican market
Necessity is once again the mother of invention. This handy tool takes the pain out of cactus thorn removal.
Put the prepared and cut up pieces in a pot with boiling, salted water. Cook for 15 to 20 minutes without a lid. When the leaf-pads are cooked, pour off the water and then rinse with cold water. The nopalitos can now be used in salads, stews or as a vegetable.