To prepare jars: place jars (without lids or rims) in an upright position in a water canner or large stockpot with a rack and fill with hot water. Cover the jars with water by about 1 inch. Cover with a lid and bring to a simmer; keep jars in a low simmer until ready to fill. Place lids in a separate saucepan and keep on low heat to keep warm for sealing. Leave clean bands nearby.
In a large saucepan, whisk together the 2 ½ cups granulated sugar, ¾ cup Clear Jel *cooking type ½ tsp ground cinnamon, and ¼ tsp ground nutmeg. Whisk in the 2 cups cold water, whisking until no clumps remain.
Bring to a boil over medium heat, whisking frequently. Once the mixture comes to a boil, cook 1 minute while whisking constantly.
Add in drained 10 cups freshly peeled & sliced peaches and ¾ cups bottled lemon juice; stir gently over medium heat an additional 2 minutes. Remove from heat, add in 1 tsp almond or amaretto flavoring (if using).
Using a ladle and funnel, carefully spoon hot pie filling into jars and leave 1” headspace at the top. Use a knife or skewer to remove any large air pockets. Wipe each rim of jar with a clean kitchen towel or paper towel. Then place a warm lid on top and then a band and screw on tight. *Any pie filling that does not fill an entire jar will need to be refrigerated for immediate use.
Place filled jars back into water canner or large stockpot using tongs or jar lifter. Ensure jars are still covered by at least 1″ of water. Place lid on water canner or stockpot and bring to a full boil. When the water is boiling, set timer and allow jars to process according to your altitude * see below for processing times
Remove from heat, take lid off water canner or stockpot and allow jars to sit in water 5 minutes. Then, carefully lift jars out using jar lifter or tongs and place on a kitchen towel and dry them off.
Check to see if the jars are sealed by pressing down on the top of each lid. It is firm and does not move, it is sealed. Jars can still “pop” (seal) for several hours after removing from water bath after processing. If the lid still bounces after several hours, it is unsealed and will need to be refrigerated for immediate use.