First prepare the filling. Heat the milk in a pan.

In another bowl, mix the sugar, vanilla sugar and custard with the eggs. Slowly pour in the milk and continue to mix. Place the mixture on the hob and bring to the boil until the mixture becomes relatively thick. Set aside and leave to cool until almost cold, then fold in the whipped cream. Place in the fridge.

For the dough, bring the water, butter and salt to the boil. The butter must be completely melted. Pour the flour into the hot liquid all at once and stir vigorously (on the hob) until the mixture separates from the bottom of the pan in a lump, then leave to cool slightly.

Preheat the oven to 170°C fan.

Gradually stir 4-5 eggs (depending on the size) into the batter (using a mixer). The batter should be smooth and shiny. Process the dough immediately rather than leaving it to rest.

Spread a little water on a baking tray. This is enough to prevent the dough from sticking. Place the dough in a piping bag with a large nozzle and pipe approx. 12 cm long strips. Bake in the oven for approx. 35-40 minutes on the lowest shelf position. Do not open the oven during the baking time.

Allow the eclairs to cool slightly before cutting them in half horizontally. Set the lid aside. Scrape out the inside a little with a spoon. Use another piping bag to fill the eclairs and place the lids on top. Now either sprinkle with icing sugar or brush with icing.

For the icing, first sieve the icing sugar into a bowl, then slowly add the water and mix well with a whisk until the icing is thick.