Place the carrots in a large saucepan with the cumin and a pinch of salt and fill with just enough water to cover the carrots. Bring to the boil, then reduce the heat and simmer for 20 minutes, until soft. Drain the carrots, then blitz in a blender until very smooth. Leave to cool.
Preheat the oven to 220°C/gas mark 7. Place a baking tray in the oven to preheat.
Grease the base and sides of 6 x 250ml ramekins with butter. Sprinkle the ramekins with flour or breadcrumbs, rotating them to coat the base and sides. Turn the ramekins upside down and gently tap to remove any excess flour or crumbs.
Melt the 50g of butter in a saucepan over a medium heat, until foaming. Add the flour and cook, stirring, for 2 minutes, until the mixture bubbles and starts to come away from the sides of the pan. Remove from the heat, add half of the milk and whisk until smooth. Add the remaining milk, return to the heat and cook, stirring, for 3 minutes, until the mixture boils and thickens. Remove from the heat again and add the grated cheese and carrot purée. Stir until the cheese melts and the mixture is smooth, then add the egg yolks and stir until well combined. Season with salt and pepper.
Use an electric mixer to whisk the egg whites in a clean, dry bowl until soft peaks form. Add one-quarter of the egg whites to the cheese mixture, using a metal spoon to fold through until just combined. This will loosen the mixture. Add the remaining egg whites and gently fold until just combined.
Divide the carrot mixture between the ramekins and smooth the tops. Run your finger around the inside rim of each ramekin, about 2cm into the soufflé, as this will help the soufflé rise more evenly.
Place the ramekins on the preheated tray and bake for 10 minutes, until golden brown and puffed up. Serve immediately.