In a large pot, melt the butter over medium-low heat and add the onions. Saute onions for a few minutes until tender. Add the squash, broth, marjoram, pepper and cayenne and stir together. Cover the pot and bring the mixture to a boil. Turn the heat down to a simmer and simmer covered for 20 minutes or until the squash is tender.

When soup is done cooking, add the cream cheese and puree the soup completely, either by using an immersion blender directly in the pot or by pouring the soup in batches into a normal blender, until smooth. Sprinkle a bit of Pumpkin Pie Spice on each serving.