Preheat the oven to 350°F. Line a mini muffin tin with 48 mini cupcake liners (this recipe makes approximately 48–54 mini cupcakes depending on size).
In a large bowl, combine the spice cake mix, eggs, oil, apple cider, sour cream, and cinnamon. Mix until smooth. Gently fold in the diced apples and Biscoff cookie crumbs.
Fill each cupcake liner about 2/3 full. Bake for 9–11 minutes or until a toothpick inserted in the center comes out clean. Let cupcakes cool completely.
To make the frosting, beat the softened cream cheese and butter until fluffy. Gradually mix in the powdered sugar, one cup at a time. Add vanilla, cinnamon, and just enough heavy cream or milk to create a smooth, pipeable consistency.
Pipe or spread the frosting onto the cooled cupcakes. Top each one with a sprinkle of Biscoff crumbs and a drizzle of caramel, if desired.