01 - In a large, heavy-bottomed pot, combine apples, lemon juice, apple cider, and water. Simmer over medium heat, stirring occasionally, for about 10 minutes or until apples are tender.
02 - Use a potato masher or immersion blender to slightly mash the apples, retaining some small pieces for texture.
03 - Stir granulated sugar, brown sugar, cinnamon, nutmeg, allspice, and salt into the pot. Mix thoroughly to dissolve all sugars.
04 - Add butter cubes to the mixture. Cook over medium heat, stirring frequently and scraping bottom, until mixture thickens and turns golden caramel, about 20–25 minutes.
05 - Increase heat to bring the mixture to a rolling boil. Add liquid pectin and stir well. Continue boiling hard for 1–2 minutes, then remove from heat.
06 - If necessary, skim any foam from the surface. Ladle hot jam into sterilized jars, leaving 1/4-inch headspace. Wipe rims, apply lids, and process jars in a boiling water bath for 10 minutes (adjust for altitude if needed).
07 - Allow jars to cool completely. Store in a cool, dark place; refrigerate after opening.