Potato - beetroot curry

Ingredients

• 4-5 medium- sized potatoes
• 2 beetroot
• 4 onions, finely sliced
• 1 tablespoon cooking oil
• 1 teaspoon mustard seeds
• 1 teaspoon jeera seeds
• ½ teaspoon urad dal
• 1 spring curry leaves
• 2 green chillies, slit lengthwise
• 1 - inch piece ginger
• ½ teaspoon turmeric powder
• 1 teaspoon red chilli powder
• Salt to taste
• 1 cup water