Put chocolate and butter in a heatproof bowl and set over a pan of simmering water (the bottom of the bowl should not touch the water) and melt, stirring often.

While your chocolate butter mixture is cooling. Butter your pan and line with a parchment circle then butter the parchment.

Separate the egg yolks from the egg whites and put into two medium/large bowls.

Whip the egg whites in a medium/large grease free bowl until stiff peaks are formed (do not over-whip or the cake will be dry).

With the same beater beat the egg yolks together.

Add the egg yolks to the cooled chocolate.

Fold in 1/3 of the egg whites into the chocolate mixture and follow with remaining 2/3rds. Fold until no white remains without deflating the batter.

Pour batter into prepared pan, the batter should fill the pan 3/4 of the way full, and bake at 375F/190C

Bake for 25 minutes until an instant read thermometer reads 140F/60C. Note – If you do not have an instant read thermometer, the top of the cake will look similar to a brownie and a cake tester will appear wet.