01 - In a large, heavy-bottomed pot, combine chopped apples, lemon juice, apple cider, and water. Bring to a simmer over medium heat and cook for approximately 10 minutes, stirring occasionally, until apples are tender.
02 - Using a potato masher or immersion blender, gently mash the cooked apples, retaining some small chunks for a pleasant texture.
03 - Add granulated sugar, brown sugar, ground cinnamon, nutmeg, allspice, and salt. Stir to fully dissolve sugars and distribute spices evenly.
04 - Stir in unsalted butter cubes. Continue cooking over medium heat, stirring frequently and scraping the bottom to prevent scorching, until the mixture thickens and achieves a golden caramel color, 20 to 25 minutes.
05 - Bring the mixture to a full rolling boil. Stir in the liquid pectin and boil hard for 1 to 2 minutes, then remove from heat.
06 - Skim foam as needed. Ladle hot jam into sterilized jars, leaving 1/4-inch headspace. Wipe jar rims, secure lids, and process jars in a boiling water bath for 10 minutes, adjusting time for altitude if needed.
07 - Let jars cool completely at room temperature. Store in a cool, dark place, and refrigerate after opening.