In Penang's nyonya cuisine, I have come across some dishes with the word "Belanda" in its name previously, and one of it was Belanda Egg. And it was quite similar to today's dish - Belanda Hu (with Hu meaning fish in hokkien), with the similarity being the tamarind used in the gravy. It is a nice sweet and sour dish that goes very well with steamed white rice as I recalled.
One important point to note is to use tamarind pulp with seeds in order to get a thick gravy. From my past experience of using seedless tamarind pulp, the gravy turned out very diluted and it won't thicken at all so I had to resort to cornstarch solution in the end.
300g threadfin (kurau/senangin) steaks
6 shallots (sliced)
4 large cloves of garlic (sliced)
50g tamarind pulp rubbed with 125ml water, then strained to get the juice
1 red chilli (sliced)
2 tbsp sugar *I used 3 tbsp*
salt to taste *I omitted*
1/ Put in 3-4 tablespoon of oil into a frying pan and slowly sauté the shallots on medium heat until golden, then drain and dish up.
2/ Saute the garlic slices until golden and crisy, then drain and dish up too.
3/ Fry fish steaks until golden with the remain oil, then drain and dish up.
4/ Put cinnamon stick into the pan (still with oil) and on medium low heat, cook this for 1 minute.
5/ Pour the tamarind juice into the pan, put chilli and reduce gravy to the desired consistency. Adjust the taste with sugar and salt.6/ Put half the crispy shallot and garlic into the gravy, then add in the fried fish steak to simmer for 10 seconds and dish up.
7/ Serve sprinkled with the remaining crispy shallot and garlic.