Prepare the apples: Peel, core, and slice the apples evenly. Toss them with lemon juice to prevent browning and maintain freshness. Mix sweet and tart varieties for the best flavor balance.
Cook the filling: Place the apples in a medium saucepan over medium heat. Add sugar substitute, cinnamon, nutmeg, and cloves. Stir gently and cook until the apples begin to soften, about 5–7 minutes.
Thicken the filling: Mix cornstarch with water to make a smooth slurry. Slowly pour it into the apple mixture while stirring continuously. Cook for another 2–3 minutes until the filling thickens to your desired consistency.
Add optional flavors: Stir in vanilla extract and unsweetened apple juice if desired. This enhances the aroma and depth of flavor.
Cool and store: Remove the filling from heat and let it cool completely. Transfer to an airtight container. Store in the fridge for up to 7 days or freeze for up to 3 months.
