Peel and cube the pumpkin into evenly-sized pieces, then chop the onion, mince the garlic, and grate the ginger.
Heat the oil in a large skillet over medium heat until shimmering, then add the chopped onion. Sauté for about 5 minutes until translucent and fragrant, with a gentle sizzle and slightly golden edges.
Add the minced garlic and grated ginger to the skillet, stirring constantly for about 1 minute until aromatic and fragrant, filling the air with a warm, spicy scent.
Stir in the pumpkin cubes, coating them with the aromatic mixture, and cook for another 5 minutes until they start to soften and turn slightly golden around the edges.
Sprinkle in the curry powder, turmeric, and cumin, stirring to toast the spices for about 30 seconds until fragrant and slightly darker in color.
Pour in the coconut milk, stirring gently to combine everything into a creamy sauce, then bring to a gentle simmer. This will help the flavors meld and the pumpkin to cook through.
Lower the heat, cover the skillet, and let the curry simmer for 20-25 minutes, stirring occasionally, until the pumpkin is tender and the sauce has thickened to a luscious consistency.
Uncover the skillet and taste the curry, adding salt as needed. Squeeze in fresh lime juice to brighten the flavors, then stir to combine.
Serve the warm pumpkin curry over steamed rice or with crusty bread, garnished generously with chopped fresh cilantro for a burst of freshness and color.