01 - Combine chopped apples, lemon juice, apple cider, and water in a large, heavy-bottomed pot. Bring to a simmer over medium heat and cook for 10 minutes, stirring occasionally, until apples are tender.
02 - Using a potato masher or immersion blender, lightly mash the softened apples, keeping some small pieces for texture.
03 - Add granulated sugar, brown sugar, ground cinnamon, nutmeg, allspice, and salt. Stir thoroughly until all sugars have completely dissolved.
04 - Stir in the cubed unsalted butter. Continue cooking over medium heat, stirring frequently to prevent scorching, until mixture becomes thick and adopts a golden caramel hue, about 20 to 25 minutes.
05 - Increase the heat and bring mixture to a full boil. Add the liquid pectin, stir fully, and boil hard for 1 to 2 minutes. Remove the pot from heat.
06 - Skim off any foam if needed. Use a ladle to transfer hot jam into sterilized jars, leaving 1/4-inch headspace. Wipe rims, secure lids, and process in a boiling water bath for 10 minutes, adjusting for altitude as required.
07 - Allow jars to cool entirely at room temperature. Store unopened jars in a cool, dark place. Refrigerate after opening.