1. Pour stock into a deep cooking pot and turn heat to medium-high. Add prepared lemongrass to the pot, including upper parts of the stalk you didn't mince. Boil 5 to 6 minutes, or until fragrant.
2. Reduce heat slightly to achieve a nice simmer. Add garlic, chili, lime leaves, and mushrooms to broth. Continue simmering for another 5 minutes.
3. Add shrimp, bell pepper, and cherry tomatoes (if using). Simmer 5-6 minutes, or until shrimp are pink and plump.
4. Turn down the heat to low and add 1/2 can coconut milk plus fish sauce. Test-test the soup for spice and salt, adding more chili and/or fish sauce (instead of salt) as desired. If too sour for your taste, add 1 tsp. brown sugar; if too salty, add a squeeze of lime juice. Add more coconut milk if you want your soup richer/creamier, or if it's too spicy for your taste.
5. Serve in bowls with fresh coriander sprinkled over. Enjoy!! 

Variations: