Take a bowl add prawns, turmeric powder,chilli powder, pepper powder, ginger garlic paste, vinegar, and salt.
Mix all the ingredients well. Keep aside for 30 minutes or refrigerate.
Heat 1 tsp oil in a pan add marinated prawns in it , close with a lid and cook for 2 minutes in medium flame.
Open the lid and just sauté it. Then cook again 2 minutes. The prawns cook with its own water, no need to add water.
Once the water completely gets dried up, at this stage the prawns gets cooked well. Remove it from the stove.
Heat oil in another pan and fry the coconut slices in medium flame. Stir it continuously. Remove the fried pieces and keep aside.
Heat oil in the same pan and add chopped shallots, green chilli and curry leaves. Sauté until it becomes golden brown colour.
Add chilli powder, coriander powder, and garam masala to it. Sauté it well.
Add cooked prawns and fried coconut pieces in it and roast on low heat until prawns get roasted well with this.
Serve hot with steamed rice, chapatti etc...