Combine sugar, corn syrup, salt and 3 Tbsp water in a medium pan over high heat. Bring mixture to a boil. Using a candy thermometer, boil until mixture reaches 238-240 degrees.

In a large bowl, combine remaining 3 Tbsp water with gelatin powder. Do not stir.

Once the sugar mixture reaches temperature, slowly pour it into the gelatin mixture while constantly stirring. Beat for 10 minutes with mixer. Stir in vanilla.

Spray a loaf pan with nonstick cooking spray. Spread mixture into loaf pan and let set for at least 3 hours.

Spread work surface with powdered sugar and transfer marshmallows to surface. Using a knife dipped in powdered sugar, cut into squares. Place in freezer for 10-15 minutes.

Heat chocolate chips for 30 seconds in microwave. Stir until smooth. Remove marshmallows from freezer and dip into melted chocolate. Place on parchment paper and let set for 5 minutes. Serve with warm chocolate milk or hot chocolate.