Turn your oven to 200°C/ 400°F/ Gas Mark 6

Place a baking parchment on a large rectangular baking tray or two small rectangular trays

Sieve the flour into a bowl and add the xantham gum and baking powder and leave it to one side. 

Put the water, sugar and butter into a large saucepan. Place the pan over a medium heat to melt the butter. 

As soon as the butter has melted, turn up the heat and bring the mixture to the bowl. Then turn off the heat. 

Add in the flour in one go, and beat the mixture with a wooden spoon. 

Keep beating until the mixture is fluffy like scrambled egg. 

Break the eggs into a separate bowl and whisk and then gradually add the egg mixture to the pan, beating the mixture well each time you add some. 

Put teaspoonfuls of mixture onto the baking tray, making sure there is enough space for the buns to puff up. 

Bake for 20 minutes until they are golden brown. Make a slit in each one and leave to cool. 

Whisk the cream with an electronic whisker until it is like whipped cream. Add in the icing sugar and whisk again. 

Break the chocolate chunks, and place in a bowl with the margarine or butter and melt in a bowl over a saucepan of hot water. 

Teaspoon the chocolate over the top of each puff. Leave the chocolate to harden. 

Enjoy!