Set a large soup pot on the stove over medium heat.

Pour the neutral oil into the pot and let it heat for about 30 seconds.

Add the sliced onion to the pot with a pinch of the salt.

Cook the onion for 4 to 5 minutes, stirring often, until it softens and looks glossy.

Add the sliced garlic to the pot.

Cook the garlic for 30 seconds, stirring, until it smells fragrant but is not browned.

Add the halved grape tomatoes to the pot.

Cook the tomatoes for 4 to 5 minutes, stirring now and then, until several tomatoes slump and release juice into the pot.

Add the green beans to the pot and stir to coat them in the tomato mixture.

Pour the vegetable broth into the pot and raise the heat to high.

Stir in the tamarind concentrate and the remaining 1 teaspoon salt until the tamarind is fully mixed into the broth.

Bring the soup to a boil, then lower the heat to a steady simmer.