I made this bento for my 15 year old niece. I am somewhat new at mashed potato sculpture but I enjoy it. It seems to be very versatile. To make the mashed potatoes I added a little butter, milk, and shredded white cheddar cheese to cooked potatoes and then mashed until it was the consistency I wanted.
Top: Butterfly (mashed white potato , red pepper, carrot, blue potato), broccoli
Bottom Left: Watermelon cut with butterfly cutters
Bottom Right: Pistachio nuts