In a saucepan, over medium heat, melt the butter, sugar and salt in the water. Bring to a slow boil. Add the flour. Stir continuously until the mixture comes from the bottom of the pot. This process takes about 1 minute. Remove from the heat.
Put the mixture in your food processor / mixer. Start mixing to cool it down, before you add the eggs one by one, mixing the eggs in well.
Pour the mixture into a piping bag.
On a greased baking tray, pipe 16 circular puffs.
Bake at 180°C for 25 minutes.
Set aside to cool.
Filling
In a saucepan, heat the butter over medium heat. Add the flour and stir to a paste. Add the milk little by little and keep stirring to prevent lumps. Season to taste and add cheese. Stir until melted.
In a frying pan, fry the diced onion, garlic and chilli. Add the bacon. Add to the cheese sauce. Stir in the parsley.
Set aside to cool.
Slice the puffs in half and fill them with the cheese sauce. Garnish with parsley.