Heat the soy milk enough to dissolve the coffee. 
Set aside.
Heat the margarine and sugar and stir until caramelized.
Add the milky coffee to the margarine & sugar mix and stir well.
Blend the cornflour with a little water and add to the milky coffee to thicken to a syrupy consistency.
Add mocha sauce and stir together well.
Make candied walnuts by placing sugar in a pan. 
Once melted and coloured, add the walnuts and work quickly to coat evenly, then place on a tray covered with parchment to cool, making sure you separate each piece.
When ready to serve, cook Lamb Weston Sweet Potato Fries according to instructions, drizzle the mocha chocca sauce over and sprinkle with the candied walnuts.

Explore Alfy’s vegan world of tasty Burgers and sides:
https://www.dopplegangerburger.co.uk/