Potato And Leek Roulade with Marmalade Sauce

1. Melt half the butter, add the leek and carrot and fry gently for 3-4 minutes. Add the potatoes and continue cooking for a further two minutes. Set aside. 2. In a separate pan melt the remaining butter, stir in the flour and cook for one minute. Whisk in the milk and continue stirring over a low heat until the sauce thickens. Allow to cool slightly, then stir in the egg yolks. Combine the sauce with the vegetables and season. 3. Whisk the egg whites until stiff then fold into the sauce mixture. 4. Transfer the mixture to a lined, lightly greased swiss roll tin measuring; 32 x 23cm/13 x 9in, and cook for about 15 minutes until the roulade is firm to the touch. 5. Meanwhile lay a clean tea towel on the work surface. Place a piece of greaseproof paper the same size a the towel on top of it. 6. Mix together the fromage frais and coriander. 7. Gently heat the marmalade and orange juice together in a pan until the marmalade dissolves. Bring to the boil and boil for one minute. 8. Once the roulade is cooked turn onto the prepared paper. Roll it with the paper starting at the thin end. Wrap in tea towel and allow to stand for two minutes. 9. Unroll the toulade and spread with the filling. Roll again and transfer to a serving platter. 10. Serve the roulade immediately with the sauce.