On medium heat, cook tangzhong ingredients until the consistency of paste (about 3 minutes). Cover with a vent and place in the fridge for 10 minutes.
Combine flour, milk, egg + yolk, honey, salt, cream cheese, yeast and tangzhong in a stand mixer. Knead on medium for about 10 minutes.
Reduce speed to low and add one tablespoon of butter at a time.
Once all the butter is incorporated, increase speed to medium-low until it passes the windowpane test. Allow to rise until doubled (about 1 hour).
Lightly dust the surface with flour and roll out dough into a 12 x 16 inch rectangle. Evenly spread chocolate hazelnut spread leaving about an inch from the edges. Sprinkle on peanuts and roll from one short end to the other.
Cut a little off the sides and cut into 12 even pieces. Place in a 12 x 17 inch with 3 rolls in each row out of 4 rows. Allow to rise for 45 minutes or until puffy.
Pour 1 teaspoon milk over each roll and bake in a 350°F oven for 20-25 minutes or until it reaches an internal temperature of 190°F.
Add all the frosting ingredients into a bowl and drizzle over hot buns. Allow to cool for 10 minutes before serving.