Heat the oil in a saucepan and add the onion, cilantro stems, tomatoes, tamarind paste, paprika, turmeric, chili powder, fish sauce, vegetable stock ½ cube.
Simmer this mixture for 1-2 hours, stir once in a while, until it reduces, then use a potato masher to smash any lumps and make the sauce a bit smoother. Continue simmering the sauce.
While the sauce is simmering, cook the eggs, these are hard boiled but have a creamier yolk, use your favorite method but cut back a minute or two on the cook time, then cool with running tap water and gently peel the eggs and cut in half lengthwise.
Add the egg halves to the curry sauce and gently stir to coat the eggs, sprinkle a few cilantro leaves in and stir to mix those in.
To serve, spoon egg halves into serving bowls and top with a few cilantro leaves and have red radish, sliced cucumber, and lettuce leaves on the side.