1. Poke a hole into stem end of each apple, and insert a clean 5-inch twig, small dowel, or skewer into each hole. Set pistachios on a plate. Lightly coat a baking sheet with cooking spray.

2. Place sugar and corn syrup in a medium, heavy-bottomed saucepan over medium-high heat. Cook, stirring occasionally with a wooden spoon, until mixture is dark gold, about 15 minutes. Remove from heat, and slowly drizzle in heavy cream, stirring vigorously. Let stand for 5 minutes.

3. Dip 1 apple into caramel to coat bottom third, and remove immediately, allowing excess to drip off bottom. Dip caramel-coated apple into pistachios, using your fingers to help nuts stick to caramel. Transfer coated apple to oiled baking sheet, nut side down. Repeat with remaining apples, caramel, and pistachios. Let apples stand until set, about 30 minutes.

4. Place melted chocolate in a resealable plastic bag. Snip off the tip of one bottom corner to form a very small hole. Holding 1 apple by the twig, drizzle lines of chocolate onto apple, and let stand until chocolate is set, 5 to 10 minutes. Repeat with remaining apples and chocolate.