Stir together the pumpkin, chicken stock, half-and-half, shallot, molasses, butter, pumpkin pie spice, salt, and cayenne pepper in a large stockpot over low heat; simmer 10 minutes.
Meanwhile, place bacon in a large skillet over medium-high heat, and cook until crispy; remove to paper towels to drain, then cool and crumble.
Ladle soup into bowls. Top with bacon and blue cheese.
