Prepare the Gelatin: Sprinkle gelatin over ½ cup cold water in a stand mixer bowl. Let it bloom while you prepare the sugar syrup.
Make the Sugar Syrup: Heat cane sugar, ½ cup water, and sea salt in a saucepan over medium heat. Stop stirring and let it boil until it reaches 240°F.
Whip the Marshmallow Mixture: Slowly pour the hot syrup into the bloomed gelatin while mixing on low. Increase speed to high and whip for 8-10 minutes until thick and glossy. Mix in vanilla extract.
Swirl with Nutella & Set: Pour the mixture into a parchment-lined 8x8-inch pan. Dollop Nutella on top and swirl gently with a knife.
Let Set & Cut: Allow marshmallows to set for at least 6 hours (or overnight). Sift powdered sugar over the top, then cut into squares.
Notes
Slightly warm the Nutella before swirling for easier distribution.Store in an airtight container at room temperature for up to one week or refrigerate for up to two weeks.These marshmallows toast beautifully but watch for caramelization of the Nutella.