01 - In a large, heavy-bottomed pot, combine apples, lemon juice, apple cider, and water. Set over medium heat and bring to a simmer. Cook for 10 minutes, stirring occasionally, until apples are tender.
02 - Lightly mash tender apples with a potato masher or immersion blender, leaving some small chunks for texture.
03 - Stir in granulated sugar, brown sugar, cinnamon, nutmeg, allspice, and salt. Mix until sugars are fully dissolved.
04 - Add unsalted butter cubes. Maintain over medium heat, stirring frequently and scraping the bottom to prevent scorching. Continue cooking until mixture thickens and turns golden caramel, about 20 to 25 minutes.
05 - Bring mixture to a full boil. Pour in liquid pectin and stir well. Boil hard for 1 to 2 minutes, then remove from heat.
06 - Skim off any foam if needed. Ladle hot jam into sterilized jars, leaving 1/4-inch headspace. Wipe rims, secure lids, and process jars in a boiling water bath for 10 minutes, adjusting for altitude if necessary.
07 - Allow jars to cool completely. Store in a cool, dark place and refrigerate after opening.