Preheat the slow cooker by setting it to low and add the cubed pumpkin along with a tablespoon of olive oil, cinnamon, and cloves. Toss gently to coat the pumpkin evenly.
Add the chopped onion and minced garlic to the slow cooker, distributing them over the pumpkin pieces. Cover and cook on low for about 4 hours until the pumpkin is tender and fragrant.
Once the pumpkin is soft and cooked through, use a slotted spoon to transfer the chunks into a blender or immersion blender. Pour in the vegetable broth to help blend smoothly.
Blend the mixture until creamy and smooth, adjusting the consistency with more broth if needed. Taste and season with salt and pepper as desired.
Pour the pureed soup back into the slow cooker or a pot to keep warm. Heat gently until steaming and heated through, about 10 minutes.
Serve the hot, textured pumpkin soup garnished with a sprinkle of cinnamon or fresh herbs if desired. Enjoy the rich aroma and cozy flavors with a warm slice of bread.