Heat oil in large pot and sauté chopped onions, garlic and ginger over medium heat.
Once onions become translucent, add spice mixture (and salt) and fry until aromatic (this will not take long - 10-20 seconds).
Add chopped tomatoes to deglaze the pot. Then add chopped kabocha squash. Mix, then add enough water to cover the vegetables.
Bring to a boil then simmer over low-medium heat for 10-15 minutes, or until tender.
Remove from heat (let cool slightly if your blender requires it), and blend with an immersion blender until smooth. Adjust consistency by adding more water as needed. Add more salt as needed to taste.
Serve with croutons or crusty bread. (Optional: garnish with coriander.) Enjoy!