Heat oil in a large pot over medium heat. Add chicken and sauté until just browned, about 2 minutes. Add garlic and ginger and cook until fragrant, about 1 minute.
Stir in curry paste, coconut milk, vegetable broth, lime juice, coconut sugar, fish sauce and dried mushrooms. Bring to a boil (this will take about 10 minutes) then reduce heat and simmer for about 5 minutes to let the flavors develop.
Add rice vermicelli to the soup and cook according to package instructions (mine took 2 minutes).
To serve, scoop out rice vermicelli into 4 bowls (I used kitchen tongs), ladle soup on top and garnish with lots of cilantro, chopped scallions, a few red chilli slices, and a couple of lime wedges. Serve immediately (see notes about making ahead/not serving immediately).
Thai Red Curry Chicken Noodle Soup https://www.notenoughcinnamon.com/red-thai-curry-chicken-noodle-soup%e2%80%a8/