Peel and quarter potato. Boil then mash it. Add vegan sugar a little at a time and mix well. Stir in shredded coconut and spread in a pie plate or 8 x 8 pan.
Melt chocolate squares and spread over top of mixture in pan. Add chopped walnuts to the top if you like. Let chocolate harden and cut into squares.
This comes out tasting sort of like mounds bars!