Sauté the aromatics: Heat up 1 tbsp canola oil in a small pot over medium heat. Add 1 oz lemongrass, 0.5 oz galangal, and 1 tbsp minced garlic. Stir quickly for 1 minute until slightly fragrant.

Sauté the shrimp heads: Add the shrimp heads to the pot and stir quickly for 2 minutes.

Boil the shrimp heads: Add 2 cups water to the pot and bring to a boil over high heat. Once bubbling, reduce the heat to low and simmer for 5 minutes.

Remove the shrimp heads and broth: Use tongs, a spider strainer, or a slotted spoon to fish all the shrimp heads out, then transfer the broth into a bowl.

Cook the shrimp: Heat up the remaining 1 tbsp canola oil in a deep pan. Add 20 oz shrimp, 1 tsp paprika, 1/2 tsp salt, 1/2 tsp chili powder, 1/2 tsp brown sugar, 1 tbsp lime juice, 1 tsp red curry paste, and 1/2 tsp black pepper. Cook and stir for 3 minutes.

Cook the mushroom: Add 6 oz white mushroom to the pan. Continue cooking and stirring for another 3 minutes.

Cook the soup: Add the shrimp broth, 1/2 cup coconut milk, 2 oz onion, 6 lime leaves, and 6 oz tomato to the pan. Bring to a boil and cook for 2 minutes over high heat.

Add the fish sauce: Add 1/2 tsp fish sauce and give the soup a stir. Taste and adjust if needed.

Garnish and serve: Turn off the heat. Sprinkle 1 oz red jalapeno and 1/4 cup cilantro over the soup for garnish. Ladle the soup into a bowl and serve with steamed rice.