Blend the green paste: Add 3 green chilies, 6 garlic cloves, 1 tablespoons fresh ginger, roughly chopped, 2 lemongrass stalks, chopped, 0.3 cups fresh cilantro (stems and leaves), and 3 green onions, roughly chopped to a small food processor or blender with a splash of water. Blend into a smooth paste.
Fry the paste: Heat 2 tablespoons oil (for frying paste) in a large heavy-bottomed pot over medium heat. Add the green paste and fry for 4–5 minutes
, stirring constantly, until fragrant and slightly golden.
Make the chickpea flour base: In a bowl, whisk together 0.5 cups chickpea flour (garbanzo bean flour) and 4 cups vegetable broth until completely smooth with no lumps. Pour into the pot with the fried paste. Add 1 teaspoons ground turmeric, 1 teaspoons ground cumin, 1 teaspoons ground coriander, and 1 teaspoons salt. Stir well to combine.
Simmer until thick: Bring to a gentle simmer over medium-low heat, stirring often to prevent sticking. Cook until the broth is thick and creamy, similar to a smooth gravy.
Add veggies and coconut milk: Stir in 2 bell peppers (mixed colors), sliced, 1 cups mushrooms, sliced, 1 cups baby bok choy or shredded cabbage, and 1 carrots, thinly sliced. Pour in 1 cups full-fat canned coconut milk and stir to combine. Simmer until vegetables are tender but still have a slight bite.
Cook the noodles: Boil 8 ounces rice noodles (round or flat) in a separate pot according to package directions. Drain and set aside. Keep separate from the soup until serving.
Air fry crispy noodle topping: Place 1 cups dry rice noodles (for crispy topping) in the air fryer basket in a single layer. Air fry at 375°F until puffed, golden, and crunchy. Watch closely — they crisp up fast.
Assemble and serve: Place a portion of cooked noodles in a deep bowl. Ladle the hot soup generously over the top. Top with crispy noodles, 1 red onion, thinly sliced, 0.3 cups fresh cilantro, chopped (for topping), 1 teaspoons dried chili flakes, 2 tablespoons crispy fried garlic chips, and a squeeze of 4 fresh lime wedges. Serve immediately.