Prep the Apples: Wash and thoroughly dry the apples. Insert wooden sticks into the stem end and set them aside. For best results, refrigerate for 30 minutes before dipping.
Make the Candy Coating: In a saucepan, combine sugar, water, corn syrup, and cream of tartar. Cook over medium heat, stirring until the sugar dissolves. Bring the mixture to a boil without stirring, and cook until it reaches 300°F (149°C) (hard crack stage) on a candy thermometer.
Add Natural Color: Once the candy reaches the hard crack stage, remove from heat and stir in your chosen natural colorant (beet juice for red, turmeric for yellow, etc.) and vanilla extract if using. Mix gently to avoid air bubbles.
Dip the Apples: Quickly dip each apple into the hot candy mixture, rotating it to ensure an even coating. Allow excess candy to drip off, then place the apples on parchment paper to set.
Set and Serve: Let the apples cool completely at room temperature until the candy hardens. Store in a cool, dry place.
Serve with sprinkles or crushed nuts and chocolate syrup.
