In a medium mixing bowl, combine the Nutella, whole milk, heavy cream, optional granulated sugar, vanilla extract, and a pinch of salt. Using a whisk or a spatula, stir vigorously until the mixture is completely smooth and all ingredients are well incorporated.
After mixing, taste the blend to see if it meets your sweetness preference. If you desire a sweeter popsicle, gradually add more sugar, stirring until fully dissolved.
Once the mixture is well-balanced and ready, carefully pour it into popsicle molds, leaving about half an inch of space at the top of each mold to allow for expansion during freezing.
Evenly sprinkle the chopped hazelnuts on top of each filled mold. This step adds a pleasing crunch and visual appeal; then gently insert the popsicle sticks into the center of each mold.
Place the molds upright in your freezer and freeze for at least 4 to 6 hours, or until each popsicle is completely solid.
To remove your luscious popsicles, briefly run warm water over the outside of the molds for about 10-15 seconds, or gently pull them out to release.
Enjoy your indulgent Nutella popsicles immediately, or store them in a freezer-safe bag for delicious treats later on.
Notes
Serve with extra Nutella and chopped hazelnuts for a decorative touch.