Preheat the oven to 180C/350F/Gas 4.
Generously butter 4 ramekins or coffee cups. (using 1oz/25g)
Melt the chocolate in a heatproof bowl set over a pan of simmering water.
Remove from the heat and whisk in the remaining 75g/3oz of the butter until melted.
Place the egg whites in a bowl and whisk until stiff peaks have formed.
In a separate bowl, beat together the stevia and egg yolks until pale and fluffy and then pour in the cooled chocolate mixture.
Fold in the sieved plain flour then gently fold in the stiff egg whites. Spoon the mixture into the prepared individual ramekins, filling two-thirds full.
Arrange on a baking tray and bake for 12 minutes until well risen but still with a slight wobble in the middle.
To serve, leave to settle for a minutes and carefully invert onto your serving plate.
Blitz the raspberries and place in a strainer to remove the seeds. Squeeze some lemon juice over the raspberry pulp and add the stevia and water. Stir to combine.