Under warm water, wash the apples with a little soap to remove any wax or residue. Remove the stems and thoroughly dry the apples.
Chop the nuts, crush the Oreos, and prepare other toppings if using. Set aside.
Insert wooden sticks into the top of each apple where the stem was removed.
In a microwave-safe bowl, melt the caramel candies according to the package instructions. Add a teaspoon or two of evaporated milk if needed to achieve the desired consistency.
In a tall dish (such as a yogurt container), dip each apple into the melted caramel, ensuring an even coating. Use a spatula to remove any excess caramel from the bottom of the apple. Place the coated apples on a parchment-lined baking sheet.
Place the caramel-coated apples in the refrigerator and allow them to set for about 30 minutes to 1 hour.
In a microwave-safe bowl, melt the milk chocolate according to the package instructions. Stir until smooth.
Once the caramel has set, dip each apple into the melted chocolate. Quickly add your desired toppings, such as chopped nuts, crushed Oreos, or graham cracker crumbs, before the chocolate sets.
Melt the white chocolate in a microwave-safe bowl and drizzle over the top of each apple for an extra decorative touch.
Place the finished apples back on the parchment-lined baking sheet and allow them to set completely. Once set, they are ready to serve or package for gifting.