In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté for 3-4 minutes until softened and translucent.
Stir in the minced garlic and ginger, cooking for an additional 1-2 minutes until fragrant.
Add the red curry paste, turmeric, and cumin to the pot, stirring to coat the onions evenly. Sauté for another minute.
Add the diced butternut squash and vegetable broth to the pot. Bring the mixture to a boil, then reduce heat to a simmer. Cover and cook for about 20-25 minutes, or until the squash is tender.
Once cooked, remove the pot from heat and stir in the coconut milk. Use an immersion blender (or transfer to a blender in batches) to puree the soup until smooth.
Return the soup to a low heat, seasoning with salt and pepper to taste. Allow it to warm through for a few minutes.
Serve the soup hot, garnished with fresh cilantro and a lime wedge on the side for an extra burst of flavor.