In a mixing bowl, add sardines, salt, shallots and plenty of black pepper. Mix well and set aside for 10 minutes.
Scatter the tomato slices and ginger/galangal slices at the bottom of a pot or braising pan. Place the sardines on top. It's likely you cannot fit all the sardines in one layer. If so place one layer of tomatoes and ginger/galangal, then one layer of fish, repeat one layer of tomatoes and ginger/galangal and then the remaining fish on top. Add birds-eye chili.
Add the tea to the pot. The liquid should be just about enough to cover the fish. If the tea is not sufficient, add a little more hot water. Bring everything to a boil. Skim off any foam. Add caramel sauce and fish sauce, then reduce heat to a simmer.
Simmer partially uncovered for about 40-45 minutes until there is a little sauce left at the bottom. If the liquid reduces too rapidly while simmering, add a little more hot water. Taste and adjust to your liking with more fish sauce and black pepper if needed.
Place sardines in a serving plate and serve hot with rice.