Cream the shortening and the sugar together. Add the eggs, baking powder, soda, salt, and spices. Add water alternately with flour. Stir in nuts and pumpkin. Wash the 8 pint size jars in hot soapy water and allow to dry. Next grease them using a brush dipped in melted shortening.
Fill each jar 1/2 full of batter and wipe the rims clean. Bake on middle rack on cookie sheet at 325°F for 35 to 45 minutes.
Meanwhile bring pot of water to boil. Once it boils turn it off. Place the lids and rings in the water and let sit in water until ready to use. When the cakes are done, remove the jars one at a time and place the lid on (don't worry about wiping away the water, the added moisture will not hurt the cakes). Add ring and screw the lid on tightly. Let rest until cooled completely. Jars will seal on their own as they cool. Makes 8 pint size jar cakes that will last up to 6 months.
If giving as a gift, cover lid with pretty fabric and attach a card giving name of cake, date made, and expiration date.
If not for a gift, just write the info on lid with a marker.
When ready to eat, if cake does not come out easy just run under hot tap water for a few seconds or place in microwave with the lid removed for 2 seconds. Eat within 2 days after opening and store in refrigerator after it is opened.
Recipezaar Editor Note: Additional information from Clemson University Cooperative Extension Service regarding canning safety for breads and cakes.
"These products are not recommended for canning. Choose recipes that you can freeze. In fact, most of these products are not really “canned.” The directions call for baking in the jar and then closing with a canning lid. Many recipes for quick breads and cakes are low acid and have the potential for supporting the growth of bacteria like Clostridium botulinum if it is present inside the closed jar. You will see these products made commercially; however, additives, preservatives and processing controls not available for home recipes are used. Canning jar manufacturers also don’t endorse baking in their canning jars.