Prepare the vegetables for the soup and garnishes first, so they're ready to go when needed. Mince the garlic and grate the ginger using a small-holed cheese grater. Peel and dice the sweet potato into one-inch cubes. Wash the bok choy well, then chop into one-inch strips, separating the fibrous stalks from the delicate green ends. Thinly slice the red onion and roughly chop the cilantro.

Add the water to a large soup pot along with the minced garlic, grated ginger, and Thai red curry paste. Sauté the garlic, ginger, and curry paste over medium heat for 1-2 minutes.

Add the diced sweet potato and chopped bok choy stalks to the pot (save the leafy green ends for later) along with the vegetable broth. Bring the pot to a boil over medium-high heat, then reduce the heat to low and let simmer for 5-7 minutes, or until the sweet potatoes are tender.

While the soup is simmering, cook the pasta per package instructions.  Drain the pasta in a colander and set aside.

Once the sweet potatoes are tender, add the coconut milk, soy sauce, and sweetener to the soup. Stir, taste, and adjust the soy sauce or sweetener if needed. Finally, add the bok choy greens and let them wilt in the hot soup.

To serve, divide the pasta among four bowls. Ladle the soup and vegetables over the pasta, then top with red onion, cilantro, a wedge or two of lime, and a drizzle of sriracha.