Put apple pieces in a large, deep pot and toss with lemon juice.
Over high heat, bring to a boil, stirring.
Reduce heat to medium, and cook, stirring occasionally, until apples are soft, about 20 minutes.
Use an immersion blender in the pot to puree the apples.
Keep sauce at a gentle boil while ladling into hot, sterilized jars.
Wipe jar rims with a damp paper towel, and put lids and bands on jars.
Process jars in a boiling-water canner for 20 minutes.
Allow jars to cool, making sure they are sealed, and store in the pantry until ready to use.
If you don't have an immersion blender, transfer cooked apples to a blender or food processor in batches. Then return pureed apples to the pot and bring back to a gentle boil before ladling into jars.If you prefer to add cinnamon, put a cinnamon stick in the pot with the apples, then remove it before transferring the sauce into jars.Prep time given is for peeling and coring apples by hand, and if you have an apple peeler / corer, it will be much reduced.For even more apple flavour, substitute the water for apple juice or apple cider.If you prefer not to process your applesauce, it will keep in the fridge for about a week, and can also be frozen.