, peeled and sliced 1/3 inch thick.
Pour mixture into an 8 1/2- x 4 1/2-inch loaf pan.Use a spoon to skim off any bubbles from surface.
Let cool completely at room temperature, uncovered and undisturbed, until set, about 45 minutes.Run a knife along edges of pan.Flip pan over; gently tap bottom to release jelly.
Cut into 36 (1/2- to 3/4-inch) cubes.Set aside.. Bring remaining 4 cups cold water to a boil in a medium saucepan over medium-high.
Stir in salt, and return to a boil.
Add vermicelli; cook, stirring occasionally, until al dente, 1 to 2 minutes.Let the hazelnuts cool completely..
In a food processor, pulse the hazelnuts until finely chopped.In a medium bowl, using a hand mixer, beat the egg whites with the salt at medium speed until foamy, 2 minutes.
Gradually add the sugar and continue beating until soft peaks form when the beaters are lifted, 5 to 7 minutes.Fold in the hazelnuts..