01 - In a large heavy-bottomed pot, combine the chopped apples, lemon juice, apple cider, and water. Bring to a simmer over medium heat and cook for 10 minutes, stirring occasionally, until apples are softened.
02 - Lightly mash the softened apples using a potato masher or immersion blender, leaving some small chunks for texture.
03 - Add granulated sugar, brown sugar, cinnamon, nutmeg, allspice, and salt. Stir until sugars dissolve completely.
04 - Stir in unsalted butter. Continue cooking on medium, stirring frequently, until the mixture thickens and develops a golden caramel color, about 20 to 25 minutes. Scrape the bottom regularly to prevent scorching.
05 - Bring the mixture to a boil. Add liquid pectin, stir thoroughly, and boil hard for 1 to 2 minutes. Remove from heat.
06 - Skim any foam from the surface if needed. Ladle hot jam into sterilized jars, leaving a 1/4-inch headspace. Wipe rims, affix lids, and process jars in a boiling water bath for 10 minutes, adjusting for altitude if required.
07 - Cool jars completely and store in a cool, dark location. Refrigerate after opening.