1. Preheat oven to 200 °C (400 °F).
2. Butter six 125 mL (½ cup) ramekins, then sprinkle with flour. Set aside.
3. In a bain-marie, melt milk chocolate and dark chocolate together. Add a pinch of salt.
4. Set aside.
5. Using an electric mixer (hand or base), cream butter with sugar until mixture is light and airy.
6. Add eggs one at a time, beating well after each one.
7. Add vanilla extract.
8. Add flour and mix well with a mixer or spoon.
9. Add melted chocolate in the same way.
10. Fill ramekins about three-quarters full.
11. Cook until cakes have stuck to the sides, but are still soft in the centre, about 12 to 14 minutes. Let cool for 5 to 10 minutes.
12. Using a paring knife, remove cakes from ramekins and flip directly onto serving plates.
13. Before serving, whip cream until soft peaks form. Add cinnamon and icing sugar and continue whipping until stiff peaks form.
14. Top cakes with cinnamon whipped cream, sprinkle with icing sugar, and serve.

Advance preparation: If desired, prepare cakes 1 to 2 hours in advance, then cook as directed.