1. Use unwaxed apples or wash them well to remove any wax. Use a paper towel to pat them completely dry. Insert hard lollipop sticks into the center of the apples. Place on a parchment lined baking sheet and transfer to the freezer to chill while you prepare the caramel.
2. In a medium saucepan, melt the butter over medium-low heat.
3. Whisk in the sugar, syrup, condensed milk and vanilla. Stir regularly and cook until the mixture beings to boil.
4. Increase heat to medium heat and cook caramel for about 15 minutes, stirring constantly but slowly, until the caramel thickens and the temperature on a candy thermometer reads 235 °F. You can also test the caramel to see if it forms a "soft ball". This means that if you drop the caramel into cold water and then remove it from the water and roll into a ball, the caramel should keep its shape.
5. Remove saucepan from the heat. Let the caramel cool for a few minutes.
6. Dip the apples into the hot caramel and twirl to fully coat and to let any excess drip off. Hold it upright for 30 seconds before placing it top side down back on the lined pan (this is to prevent the caramel from pooling at the bottom).
7. To decorate, start decorating the apples within 5-10 minutes (before the caramel has completely set). For plain caramel apples or apples completely dipped in chocolate, transfer the apples to the refrigerator instead for 15 minutes to set completely. If the caramel pooled a little on the parchment paper,  you can leave it as is, or lift up the apple and use your hand to shape the pooled caramel around the apple.

Decorate:

1. Dip some caramel apples in crushed nuts, pretzels, and/or mini m&m's.
2. Melt the milk chocolate. Drizzle some caramel apples with melted chocolate. Add extra toppings if desired.
3. Melt the white chocolate. Drizzle some caramel apples with melted white chocolate. Add extra toppings if desired.
4. For apples completely dipped in chocolate, use caramel apples that are fully set and then dip them in the melted chocolate to coat.
5. Set aside the decorated apples back on the lined pan and let toppings harden fully.