In a large pot over medium high heat add paste, lemon grass, zest, juice, ginger and stock. Bring to a boil, stir, reduce heat and let simmer for 10 minutes.
Stir in fish sauce and sugar. Simmer another 10 minutes.
Add coconut milk, turkey, noodles and 1 tbsp cilantro. Turn heat off and let sit for 5-10 minutes or until noodles are soft.
Remove chunks of lemon grass. Season with salt and pepper.
Serve hot with garnishes.
Notes
Garnishes: chopped cilantro, red Thai chili pepper, bean sprouts, sliced green onion and lime wedges.