- Wash and dry the apples thoroughly. Remove stems and insert a wooden stick into the top of each apple. 
- Line a baking sheet with parchment paper and lightly grease it. 
- In a heavy-bottomed saucepan over medium heat, melt the butter. 
- Add brown sugar, cream, corn syrup (or substitute), and salt. Stir constantly until the sugar dissolves. 
- Attach a candy thermometer if using. Bring the mixture to a boil and continue to cook, stirring occasionally, until the caramel reaches 245°F (firm ball stage), about 10-12 minutes. 
- Remove from heat and stir in the vanilla extract. 
- Let the caramel cool slightly (2-3 minutes) so it thickens a bit for better coating. 
- Holding each apple by the stick, dip into the caramel, turning to coat completely. Let excess drip off. 
- Roll in optional toppings if using, and place each apple on the greased parchment paper. 
- Let cool completely at room temperature until caramel is set, about 30 minutes.