Warm some olive oil in a pot, and then add the pumpkin, onions, potatoes, and sprig of rosemary. Sauté for 10 minutes, stirring occasionally.
Add enough broth to cover the vegetables, and then salt and pepper to taste. Cook for about 30 minutes until pumpkin and potatoes are tender. Blend soup with hand mixer (or carefully transfer to a blender) until smooth.
Once soup is blended, add the mushrooms and cook for another 10-15 minutes, stirring. Remove from the heat.
While the soup is cooking, cut the bread into 1/2″ cubes, spread on a baking sheet with a drizzle of olive oil and salt, and put in the oven to toast until crisp and golden.
Serve the pumpkin cream soup with the croutons on top and a drizzle of extra virgin olive oil and, if desired, a garnish of freshly chopped rosemary.