Preheat the oven to 200℃ (400℉).
Place the diced pumpkin in a baking dish or tray. Tuck two sprigs of sage underneath and add the garlic cloves. Drizzle with olive oil and season with salt and pepper. Roast for 40-50 minutes until edges start to caramalise.
With Instant Pot on Sauté mode, add butter. Melt and allow to brown lightly.
Add diced onion and dried origanum and sauté until softened.
Add roasted pumpkin, garlic cloves and sage leaves (omit stems).
Add stock and parmesan rinds.
Pressure cook on High for 20 minutes.
Pan fry a small handful of picked sage leaves in a drizzle of oil until crispy. Remove and place on a kitchen towel until serving.
Release pressure once done and use a slotted spoon to remove parmesan rinds.
Blend with an immersion blender until smooth.
Add sour cream, reserving 2 tbsp for serving. Blend.
Add grated parmesan and blend.
Loosen the sour cream with 1-2 tsp of milk to drizzling consistency.
Season to taste. Serve with a swirl of sour cream, crispy sage leaves and a sprinkle of parmesan.