Set a large soup pot or Dutch oven over medium heat.

Add the olive oil to the pot and let it warm for about 30 seconds.

Add the leeks and carrots to the pot with 1/2 teaspoon of the kosher salt. Cook, stirring often, until the leeks are soft and the carrots start to lose their raw crunch, 6 to 8 minutes.

Add the sliced garlic to the pot. Cook for 30 seconds, just until it smells fragrant; do not let it brown.

Pour the vegetable broth into the pot. Stir and scrape the bottom of the pot with a wooden spoon if any vegetables are sticking.

Add the cannellini beans to the pot and raise the heat to high. Bring the broth to a full boil.

Reduce the heat to medium so the soup bubbles gently. Cook for 5 minutes to warm the beans through and lightly flavor the broth.

Add the sliced Swiss chard stems to the pot. Cook for 2 minutes so they start to soften.

Add the rice noodles to the pot and press them down into the broth. Stir once or twice so they do not clump together.

Cook the noodles for 3 to 4 minutes, stirring gently once, until they are flexible and just tender when you bite one.

Add the torn Swiss chard leaves to the pot. Stir until the leaves wilt into the soup, about 1 minute.

Turn off the heat. Stir in the lemon zest and 2 tablespoons of lemon juice.