Into a medium-size soup pot over medium heat, add the olive oil. When the oil is hot, add the shallot. Cook for 2 minutes, stirring frequently until softened. Add the garlic and continue cooking for 1 additional minute.
Into the pot, add the tomatoes, coconut milk, cashews, water, salt, and black pepper. Bring to a boil then reduce the heat to low. Simmer for 5 minutes.
Pour the soup into a high-speed blender and puree until the consistency is smooth. Alternatively, an immersion blender can be used to puree the soup right in the pot.
Adjust the seasoning to taste and serve.