Bring a large saucepan of water to a boil. Dip apples in water for a few seconds with a slotted spoon to remove any wax from skins; dry with paper towels. Let cool.

Insert sticks through bottom core of each apple.

Line a baking sheet with parchment paper. Stir brown sugar, sweetened condensed milk, corn syrup, and butter together in a medium saucepan over medium-high heat.

Bring to a boil, stirring constantly; reduce heat to medium. Cook until a candy thermometer reads 248 degrees F (120 degrees C), stirring constantly to prevent burning, 25 to 30 minutes. A teaspoon of caramel dropped in a glass of cold water should form a firm ball.

Remove from heat; stir in vanilla extract.

Working quickly, dip each apple into caramel to completely coat apple and about 1/2 inch of the handle.

Sprinkle apples with desired toppings while still hot.

Let cool on the prepared baking sheet, about 1 hour. Use caution, caramel is very hot.

Image and recipe sourced from: https://www.allrecipes.com/recipe/228210/the-best-caramel-apples/