Boil 2 cups water in a pan. Add 2 chopped beetroots, 1 garlic clove, 3-4 small onions, and 1/2 tsp salt. Cook until the beetroot is soft and water is absorbed.
Add 1 green chili, 1/8 cup cashews, and 1 tsp sugar. Cook until there is very little water left.
Stir in 1/8 cup coconut milk. Mix, turn off the heat, and let it cool.
Blend the cooled mixture into a paste. Add coriander leaves, mustard paste, and lemon juice. Blend again into a smooth paste.
In a bowl, combine purple cabbage, carrot, cucumber, apple, onion, and spring onion. Toss well.
Add the dressing just before serving. Mix and serve chilled.