Set a large pot on the stove over medium heat and add the olive oil.

Add the chopped onion to the pot with 1/2 teaspoon of the kosher salt.

Cook the onion for 4 to 5 minutes, stirring now and then, until it looks soft and glossy.

Add the sliced garlic, ground cumin, and ground turmeric to the pot.

Stir for about 30 seconds, just until the garlic smells fragrant and the spices coat the onion.

Add the rinsed red lentils to the pot.

Add the cauliflower florets to the pot and stir once to mix them with the lentils and onion.

Pour the vegetable broth into the pot and add the remaining 1/2 teaspoon kosher salt.

Raise the heat to high and bring the soup to a full boil.

Lower the heat to medium-low so the soup stays at a steady simmer, and cook for 12 to 14 minutes. The lentils should be very tender and starting to break down, and the cauliflower should be just soft when pierced with a fork.

Add the rice noodles to the pot, pressing them into the hot broth as they soften.

Cook the noodles for 4 minutes, stirring often so they separate and do not clump together.