Instructions:

In a mixing bowl, combine the grated carrots, grated cucumber, finely chopped capsicum, boiled and mashed potatoes, and mayonnaise. Mix well.
Add salt and pepper to taste and mix again.
Take a slice of bread and spread the vegetable mixture evenly on top of it. Cover with another slice of bread.
Apply butter or margarine on the outer sides of the sandwich.
Heat a sandwich maker or a griddle pan over medium heat.
Place the sandwich on the sandwich maker or griddle pan and toast until the bread turns golden brown and crispy.