Preheat the oven to 200°C.
Bring 160ml of the milk to the boil. Mix the remaining milk with the corn starch. Once the milk is hot, add the diluted corn starch and bring to the boil. Simmer at boiling point for 30 seconds.
Break the chocolate into a bowl and melt over a bain-marie or a pan of simmering water.
Mix the egg yolks into the warm milk then incorporate the melted chocolate - use a whisk to make sure that the ingredients are mixed well.
Butter your moulds - start by placing the butter at the base of the mould and then make an upwards movement to grease the edges of the mould. Repeat this process so that you have two layers of butter and then dust with sugar.
Place the egg whites in the bowl of a food processor and whisk to stiff peaks. Add the sugar and whisk for a further 2 minutes until you have a stiff, shiny mixture.
Add 1/3 of the egg whites to the chocolate mixture and mix well. Gently fold in the rest of the egg whites. Half fill your souffle moulds and then place 5 raspberries in each one. Add more of the chocolate mixture until the moulds are 3/4 full. Transfer to the oven and cook for 10 minutes.
Remove from the oven and serve immediately.
«If using 3cm wide moulds, reduce the cooking time to 6 minutes and only place 3 raspberries in each souffle.»