Wash and dry curry leaves.Take a iron skillet pan .Take a wide pan so that oil doesn't splash much.Add the oil, curry leaves, pepper corns and dried hibiscus /powder.Let it boil till the leaves change colour and look black in colour.
Add shallots and garlic when leave start looking black..Oil will sizzle when you add both the ingredients till the water content completely evaporates.
Switch off the gas.
Now let it wait for 3-4 hours I sometime keep it overnight in the iron vessel itself..
Strain the oil , squeeze out everything from the ingredients and store in a clean and dry bottle.