Vanilla Custard
It is always better to prepare the custard before the choux pastry. It will allow the custard to cool down for a few hours. Cut the vanilla bean in the middle and scrap the seeds with a knife tip. You could also use few drops of vanilla extract. Bring the milk to the boil and add the vanilla bean and seed. (or extract if using). Remove from the heat and let the milk & vanilla infused for 10 minutes. In a bowl combine egg, cornflour and sugar and whisk well until the mixture thick and white. Filter the milk through a coffee filter or sieve. Pour the warm milk into the cornflour/egg mixture and whisk vigourously. Return the mixture to the saucepan under medium heat, bring to the boil for 3 minutes while constatnly stirring. Remove from heat and add the diced butter. Stir until melted. Pour the custard into a piping bag and let it cool down for 2 hours (first hour at room temperature and then in the fridge).

Prepare the Choux Pastry
Make sure you measure all ingredients before you start. In a saucepan slowly bring to boil (medium heat) the water, milk, salt, sugar and butter. Remove from heat and add the sifted flour all at once and stir quickly with a wooden spoon. Return the saucepan under medium heat and keep stirring until a thin layer is forming on the bottom of the saucepan. This could take about 3 minutes. The dough is ready when it pulls away from the sides of the pan and forms a smooth ball. Transfer the dough to a bowl and cool for 3 minutes. Add the beaten eggs one at a time, stirring well with a wooden spoon after each addition. Each time you add eggs the dough will split into small pieces. Keep stirring until the dough absorbs the eggs. (Usually the dough does not require the 5 full eggs. It really depends on the flour you used.) The dough is ready when it is consistent - not too liquid and shiny. Preheat oven at 200C.Cover a baking tray with baking paper or use a silicon mat. Pipe the eclairs on the baking tray. Length is about 15 cm. Bake for 30 minutes or until golden brown. Do not (never ever!) open the oven door until puffed up (around 10-20 minutes depending on their size). Transfer to a rack and let cool before use. Tips: You know the choux are cooked when all the choux cracks are well brown. If they are yellow keep cooking. If you undercooked them the choux will flatten when outside of the oven. The cooking time really depend of the choux size. An eclair required around 30-40 minutes at 200C and a choux around 20-30 minutes at 200C.

Eclairs Icing
Prepare 3 bowls - one for each colour - red, blue & plain. Mix 40g of icing sugar with few drops of food colouring. Slowly add about 2 or 3 teaspoons of water, until it is thick and shiny. Not too runny, not too thick as the icing needs to set on top of the eclair. Store in plastic bags. Cut a edge of the bag to use as a piping bag.

Eclairs - Filling and Decorating
Drill 3 holes on the top of the eclairs and filled with vanilla custard using the piping bag. Place the eclairs between two baking tray to hid the sides. Start decorating with the topping prepared in the plastic bag. Swirl one colour at a time.