Preheat your oven to 170°C (340°F)/fan 150°C (300°F)/gas mark 3½. Lightly butter 10 individual muffin or dariole moulds.
Gently melt 225g (7.9 oz) of the chocolate and all the butter. You can do this in a heatproof bowl over simmering water (don't let the bowl touch the water) or in the microwave on a low setting, stirring every 10 seconds.
Set aside to cool slightly.
In a separate large bowl, whisk the eggs while gradually adding the granulated sugar.
Continue whisking until the mixture is frothy, glossy, and pale.
Pour the cooled chocolate and butter mixture into the egg mixture, mixing thoroughly until just combined. Gently fold in the halved raspberries and most of the remaining chopped chocolate, saving 10 pieces for the centers.
Divide the batter evenly between your prepared moulds. Push one of the reserved pieces of chocolate into the middle of each cake.
Bake for 15–20 minutes. The cakes should have risen and be firm to the touch, but still have a gooey, molten center.
Let them cool in the moulds on a wire rack.
While the cakes cool, make the rose cream.
In a chilled bowl, whip the cold double cream, rose water, and sifted icing sugar together until soft peaks form.
Cover and refrigerate until you're ready to serve.
To serve, carefully turn the cooled cakes out of their moulds. Decorate each one with a generous dollop of rose cream, a fresh raspberry, a light dusting of icing sugar, and a single rose petal, if using.
When melting chocolate in the microwave, use the lowest power setting and stir every 10 seconds to prevent it from burning.
