Heat 1 teaspoon of sesame oil in a large pot over medium-high heat. Sauté the scallion for 2 to 3 minutes, until just tender.
Now, cook the garlic, ginger, cinnamon, and cloves and cook for about 3 minutes until aromatic. Add the celery, carrots, and broth, and bring to a boil. Immediately turn the heat to a simmer.
Then, continue to simmer, covered, for 35 to 40 minutes. Strain out and discard the solids. Stir the cabbage and mushrooms into the hot broth. Continue simmering for about 10 minutes. Reserve the mushrooms.
Meanwhile, cook the rice noodles according to the package instructions. Drain in a strainer, then briefly rinse the noodles with cold water to prevent them from continuing to cook.
Next, heat the remaining 1 teaspoon of oil in a sauté pan over medium-high heat. Toss your tofu with cornstarch, soy sauce, and Sriracha (if using). Cook tofu cubes for about 2 minutes, until golden and crisp.
Add the reserved mushrooms to the pan and cook them for 2 minutes more, or until slightly browned.
Divide the rice noodles between four serving bowls. Ladle the hot broth and veggies into the serving bowls. Top each bowl with tofu cubes, mushrooms, herbs, and sliced chili peppers. Enjoy!