In a large pot over low heat, add a splash of neutral oil and sauté the shiitake mushrooms until they become tender and golden, about 5 minutes. Remove and set aside.

Make diagonal cuts on the lemongrass stalks and gently pound them. In the same pot, add the lemongrass, galangal, kaffir lime leaves, and red curry paste, sauté for 2 minutes until fragrant.

Pour in the vegetable broth, stirring to combine, and bring to a vigorous boil. Reduce heat to low, cover, and let it simmer for 30 minutes.

Strain the broth to remove solids, return it to the pot, and stir in vegan fish sauce, brown sugar, and lime juice. Let it simmer gently for a few more minutes.

Dice the carrots and tofu. Add them along with serrano peppers and cherry tomatoes to the broth, covering the pot again. Simmer for 15-20 minutes until veggies are tender.

Stir in the coconut milk until fully combined. Heat over low for another 5 minutes until warmed through.

Garnish each bowl with cilantro and a drizzle of chili oil if desired before serving.