Prepare your apples by washing in plain water. Cut into chunks, remove cores, and add the apples to your saucepan. Add just enough water to the pot to prevent sticking.
Cook the apples over medium-low heat to soften, stirring occasionally so to prevent sticking. After the apples are soft, turn off the heat and allow the apples to cool.
Prepare your jars and lids by washing in warm, soapy water and rinsing thoroughly. Place jar rack into water bath canner, set jars in the canner, add water, and boil jars for 10 minutes to sterilize. Warm your lids in a small pot over low heat. Keep jars and lids warm until ready to use.
Run the cooled applesauce through a Food Strainer or Food Mill to remove skins, seeds, and to smooth out the sauce.
Return the applesauce to your saucepot. Taste the applesauce and add your cinnamon (and any other spices, if using). Start out with just a little and adjust until you are happy with the flavor. Bring the applesauce to a boil over medium-high heat while stirring to prevent sticking.
Spread a kitchen towel on the counter. Use your jar lifter to remove warm jars from canner, drain, and line up on the towel. Use your canning ladle and funnel and add applesauce to warm jars leaving 1/2-inch headspace. Wipe the rims. Use your magnetic lid lifter to lift lids out of the warm water, center lid on the jar, and screw on band until it is fingertip tight.
Using jar lifter, place jars carefully into canner leaving space in between them. Once jars are all in canner, adjust the water level so it is at least one inch above the jar tops. Add more boiling water if needed so the water level is at least one inch above the jar tops. When adding water, use the hot water from the small pot your lids were in. Pour the water around the jars and not directly onto them.
When processing time is complete, turn off heat and allow the canner to cool down and settle for about 10 minutes. Spread a kitchen towel on the counter; remove the cover by tilting lid away from you so that steam does not burn your face. Use a jar lifter to lift jars carefully from canner and place on the towel. Allow the jars to cool for 12 to 24-hours. You should hear the satisfactory “ping” of the jar lids sealing.
After 12 to 24-hours, check to be sure jar lids have sealed by pushing on the center of the lid. The lid should not pop up. If the lid flexes up and down, it did not seal. Refrigerate jar and use up within a few days.