Put chopped pears, st anise and ginger into a large pot. Add 2 cups of water and 1 cup of lemo juice. Bring to a boil, reduce to a simmer,over and cook until pears are completely soft. 25-40 minutes. Remove from heat.
Fish out star anise and discard. Ladle pear mixture, liquid included innto a food mill and orce food mixture into large bowl below. Discard remaining solids seeds stems tough parts.
Measure the resulting puree and our into large 8 quart thick bottomed pan. For every cup of puree add 1/2 cup of sugar. Stir to dissolve sugar. Add the cardamom, nutmeg and lemon zest taste and adjust seasonings if necessary.
Cook on medium heat, stirring often to prevent the puree from sticking to bottom of pan and burning. Cook until mixture is quite thick and a smal amount placed on a chilled plate will not run off. This can take anywhere from 45 minutes to 2 hours of cooking depending on the batch.
While the mixture is cooking sterilize the jars for canning. To sterilize the jars eith 1) run them thorough the short cycle of a dishwasher or 2 rinse them and pace them in a 225 degree oven for 10 minutes or lace them on top of a steaming rak in a lage pot of water which you bring to a boil for 10 minutes.
When the pear butter is ready pour into, sterilized jars and seal, allowing 1/4 inch head space between the pear butter and the rims of he jars. If you plan on storing the pear butter outside of the refrigerator follow proper canning procedures. Before applying lids, sterilize them by placing them i a bowl and pouring boiling water over them. Wipe the rims of the jars clean before applying lids. Use a hot water bath for 10 minutes to ensure a good seal. Pace on a rack inside the pot with boiling water making sure that the water covers the jars by at least one inch.