Heat milk and 1/4 cup heavy cream until almost boiling.

Using a hand whisk, beat egg yolks with sugar and cornstarch. While beating vigorously, pour milk and cream mixture into egg-yolk mixture. Mix well and pour the combined mixture back into the pot. Cook, stirring constantly, until thickened.

Remove from heat and add chocolate and praline paste. Add butter and mix well, until thoroughly combined. Cover mixture with plastic wrap, pressing down so that plastic wrap is touching the mixture’s surface as much as possible. Refrigerate for two hours.

Remove from fridge and beat for three minutes in mixer on medium speed. Whip up the remaining 1/4 cup heavy cream. Separate one third of the chocolate-nougat mixture and fold in whipped cream.

In a mixer fitted with the dough hook attachment, beat butter with brown sugar and salt for about four minutes. Add egg yolks, hazelnuts and flour, and continue mixing just until a dough forms; do not mix past that point! Refrigerate dough for one hour.

Preheat oven to 350 degrees Fahrenheit. On a floured surface, roll out dough about .3 inch (1 cm) thick. Use a sharp knife to cut the dough into .3-inch (1-cm) squares. Place pastry squares on a baking sheet lined with Gefen Parchment Paper and bake for about 12 minutes, or until golden.

Lay out 24 cups for serving. At the bottom of each cup, place four tablespoons of the chocolate–nougat mousse without the cream. On top of that, place one and a half tablespoons of the mousse with the cream. Tilt the cups back and forth gently to even out the mousse. Sprinkle hazelnut squares on top of the mousse layers.