Peel, core, and chop 2 lb (1 kg) tart apples. Place in a large saucepan with 3 tablespoons light brown sugar, ¼ cup(2 fl oz/60 ml) water, and 1 teaspoon fresh lemon juice and stir to combine. Bring to a boil over medium-high heat, then reduce the heat to low, cover, and simmer, stirring occasionally with a wooden spoon, until the sauce is thick and slightly chunky, about 20 minutes. Taste and adjust the flavorings, adding more sugar or lemon juice if needed. Serve warm, or let cool and store in an airtight container in the refrigerator for up to 3 days or in the freezer for up to 4 months.