Prepare the apples: Wash each apple thoroughly and pat completely dry with paper towels. Wipe each one with a cloth soaked in apple cider vinegar, then do another final pass with a clean towel. Insert a skewer into the stem end of each apple, twisting gently until it's secure. Set aside on a parchment-lined baking sheet.
Make the salted caramel: In a heavy-bottomed saucepan over medium heat, add the granulated sugar and stir constantly with a wooden spoon or silicone spatula for about 3-4 minutes until the sugar melts and turns amber colored. Don't let it burn — you're looking for a deep golden color, not dark brown.
Add butter: Once the sugar is melted and golden, carefully add the butter cubes one at a time, whisking gently between each addition. The mixture will bubble vigorously. Continue cooking until all butter is incorporated and the caramel looks smooth, about 2-3 minutes more. Remove from heat.
Finish the caramel: Slowly pour in the warmed cream while whisking constantly (the caramel will bubble up again). Add vanilla extract and kosher salt. Whisk until completely smooth and glossy. Let cool for 5 minutes — it should thicken slightly but still be pourable.
Prepare chocolate for dipping: Melt the semi-sweet chocolate chips with coconut oil in a microwave-safe bowl, heating in 30-second intervals and stirring between each. Repeat until smooth. Do the same with white chocolate chips separately.
Dip the apples: Hold each apple by its skewer and lower it into the salted caramel mixture. Turn slowly to coat evenly. Let excess drip off for a few seconds, then place on parchment paper. Immediately sprinkle with flake sea salt while still warm, or add other toppings if desired.
Add chocolate drizzle: Once all apples are coated in caramel and cooled enough to handle (about 5-10 minutes), dip the bottom third of each apple into melted semi-sweet chocolate. Lift out and let excess drip off. For a decorative touch, melt white chocolate separately and pipe thin lines across the top using a zip-top bag with a tiny corner snipped off.
Set completely: Allow apples to set at room temperature for 30-45 minutes, or refrigerate for 15 minutes if you're in a hurry. Serve immediately or store as noted below.
