Warm olive oil and butter in a medium pot over medium heat.
Soften the onion for about 5 minutes, stirring often until translucent.
Stir in garlic, cinnamon, nutmeg, ginger, and thyme; cook until fragrant, about 30 seconds.
Add pumpkin puree and maple syrup; cook 1 minute, stirring to coat.
Pour in vegetable broth and bring to a gentle simmer.
Simmer uncovered for 12 to 15 minutes, stirring occasionally.
Blend until smooth with an immersion blender, or carefully blend in batches.
Stir in heavy cream and lemon juice; season with salt and pepper. Warm 2 minutes and serve with pepitas.