Add the sliced shallots and 1/4 cup of vegetable oil to a small wok set on low heat (it is imperative that you add the shallots to cold oil lest they burn before crisping up). Stirring constantly, cook the shallots until they are golden brown and crispy. With a slotted spoon, transfer the fried shallots to a paper towel-lined plate; set aside

Place the pot on medium-high heat. Once the oil is hot, gently drop the hard-boiled eggs into it. Stir the eggs around to ensure even browning. Once the egg exteriors are thoroughly browned, fish them out with a slotted spoon, slice them in half with a serrated knife, and arrange the halved eggs on a serving platter.

Use oil from fried the shallots on medium heat. Add the brown sugar, fish sauce, tamarind, and water to it; bring the mixture to a gentle boil, stirring constantly. Once the sugar has fully dissolved, check for consistency. The sauce should have the consistency of maple syrup. If at this point the sauce is still too thin, reduce it down a bit more. If it is too thick, add a little more water to thin it out. Remove the wok from heat and pour the sauce over the prepared eggs.

Sprinkle the fried shallots over the top of the eggs. Garnish with red pepper slivers and coriander leaves. Serve son-in-law eggs with steamed jasmine rice.