Heat the oven to 180 C, no fan

Line the tray with baking paper using release spray to stick down. Brush the paper sparingly with melted butter.Set aside.

Melt the chocolate and butter gently in a saucepan. Remove from the heat and stir in the sugar and vanilla extract. Leave to cool slightly.

Whisk the eggs into the mixture a little at a time, then fold in the sifted flour and a little salt until you have a smooth mixture.

Place into the tray. Place on the middle shelf of the oven and cook for 20 minutes, then check and turn. Cook remainder of 15 mins and check.

Completely cool before serving