Slice the pineapple and cucumber to small pieces.

Grind together turmeric, cumin and coconut powder with little water into a very thin paste.

Heat oil in a pan or a kadai.

Splutter mustard seeds.

Add black gram and allow it to turn brown.

:- Do not allow it to turn black.

Add onions and saute, till they turn brown.

Add pineapple slices and a pinch of salt and stir for 3 - 5 mins.

Add cucumber, chillies and salt.

Add the coconut-turmeric-cumin mix and mix well.

Cover the pan and cook, until the cucumber is done.

Turn off the heat and wait for 3 mins.

Add curd and mix well.

:- Check the level of salt and add, if necessary.

:- You can also use other vegetables instead of cucumber, for e.g. papaya along with pineapple.

:- Curd is better than butter milk. You can use both to make this curry. However, if you use butter milk, it will be more watery and sour.