Wash and clean the shrimp well, then toss them with a pinch of salt and a little turmeric.
Heat 1 tablespoon oil in a kadai or skillet over medium heat.
Lightly fry the shrimp for about 1 minute per side, then remove and set aside. Do not overcook.
Add the remaining oil to the same pan.
Add the sliced onion and cook until soft and lightly golden.
Stir in the ginger paste and green chilies, then cook for about 30 seconds.
Add the sliced bottle gourd along with the turmeric powder, red chili powder if using, salt, and sugar.
Cook on medium heat, stirring occasionally, until the bottle gourd softens and releases water.
Cover and cook for 10 to 12 minutes until the lau becomes tender and most of the moisture cooks off.
Add the fried shrimp back to the pan and mix gently.
Cook for another 3 to 4 minutes so the flavors blend together.
Garnish with fresh cilantro if desired and serve warm with rice.