In a medium stock pot over medium heat, add 2 tablespoons of vegetable oil. Once shimmering, add 1 medium diced onion and sauté until softened, about 5 minutes. Stir in 3 minced garlic cloves, 1/2 teaspoon ground cumin, 1 tablespoon red curry paste, and 1 teaspoon brown sugar; cook for another minute until fragrant.

Pour in 4 cups of vegetable stock, followed by 2 inches of peeled ginger, 2 inches of smashed lemongrass, and 8 peppercorns. Add 1 sliced jalapeno, 1/2 cup cilantro, and 2 tablespoons fish sauce. Bring to a boil, allowing flavors to infuse for about 5 minutes.

Reduce the heat to low and let the soup simmer for 30 minutes to meld flavors, stirring occasionally.

After simmering, strain the mixture through a fine-mesh sieve into a clean bowl or pot. Discard solids and return broth to medium heat.

Add 1 can of coconut milk, stirring until combined. Then, add 3/4 pound of shrimp and 2 sliced mushrooms. Cook until shrimp is pink and opaque, about 5 minutes.

Squeeze in the juice of 1 lime, taste, and adjust seasonings. Serve immediately and garnish with additional cilantro and jalapeno slices.