1. Preheat the oven to 210C. Spray 6, 150g ramekins with nonstick baking spray. Coat 6, 150g ramekins with a light coating of butter and castor sugar. Tap out the excess.
2. Combine the chocolate and butter in a microwave safe bowl. Microwave for 1 minute. Remove from the microwave. Stir, then continue heating for 30 second, stir in between, until the chocolate is melted and smooth. Be careful and overheated chocolate can easily split and spoil the dessert.
3. Gently stir in the flour, chilli flakes and salt.
4. In a bowl whisk the eggs, egg yolks, vanilla, and the 1/2 cup of castor sugar until thick and pale. It should be able to hold the shape of ribbons. Gently fold in the melted chocolate mixture into the egg mixture. Place the batter among the ramekins.
5. Bake for about 10 minutes until the edges are firm but the center is runny.
6. Run a knife around the edges to loosen and invert onto dessert plates. Dust with icing sugar and serve immediately.