In a saucepan, melt the butter with the milk, sugar and salt. Bring to a boil and add the flour. Oft the heat, add the eggs one by one, mixing until a smooth paste is obtained.
Place the dough in the freezer bag and cut a lower corner to form a piping bag. On a lined baking tray, pipe as many eclairs as possible that are 15 cm long, and bake in the oven for 6 minutes at 180°C.
Whip the cream with a whisk and add the Nutella®. Place this mixture in another freezer bag and use it also as a piping bag for stuffing the eclairs with the chocolate cream.
Melt the milk and white chocolates, and draw lines in the milk chocolate with the white chocolate. Then dip the eclairs into the chocolate. Arrange the Kinder® toppings on top an enjoy.