(6-ounce) jar maraschino cherries, drained and chopped
2 1/2 c. granulated sugar
1/2 c. light corn syrup
2 large egg whites, at room temperature
1/4 tsp. kosher salt
1/4 tsp. cream of tartar
1 1/2 tsp. pure vanilla extract
1 c. chopped toasted pecans
1. Place maraschino cherries on a plate lined with paper towels; blot dry. Line baking sheets with parchment paper.
2. Stir together sugar, corn syrup, and 1/2 cup water in a saucepan. Bring to a boil over medium heat. Cook, without stirring, until a candy thermometer reads 260°F, 8 to 9 minutes.
3. Meanwhile, beat egg whites, salt, and cream of tartar with an electric mixer on medium speed until stiff peaks form, 3 to 4 minutes. (If egg whites are ready before syrup, decrease mixer speed to low to slow process until syrup is ready.) Increase mixer speed to medium-high and gradually drizzle the hot syrup into egg whites in a thin, steady stream, 1 minute. Increase speed to high and beat until candy is beginning to lose its gloss and holds its shape when dropped from a spoon, 4 to 6 minutes. Immediately stir in vanilla, pecans, and cherries.
4. Working quickly using 2 spoons, drop candy by heaping spoonfuls onto prepared baking sheets. Let stand at room temperature, uncovered, overnight. Store at room temperature in an airtight container up to 2 weeks.