Preheat oven to 200C. Place pumpkin skin-side down on an oven tray lined with baking paper, drizzle with 40ml olive oil, season to taste, roast until very tender and caramelised (50 minutes-1 hour). Scoop flesh out of skins (discard skins), set aside.
Heat butter and remaining olive oil in a saucepan over medium heat, add onion and garlic, sauté until golden (6-8 minutes). Add pancetta, sauté until crisp (2-3 minutes), add pumpkin, stock and thyme. Bring to the simmer, cook until flavours infuse (8-10 minutes). Process with a hand-held blender until very smooth, stir through parmesan and vinegar, season to taste and keep warm.
For parmesan toast, preheat grill to high. Combine all ingredients except bread in a bowl. Grill one side of bread slices until golden (1-2 minutes), turn and spread with parmesan butter. Grill until golden (1-2 minutes), serve with soup topped with crisp pancetta and extra thyme.