Melt butter in a saucepan over medium heat and add bell pepper and celery. Cook and stir until softened, about 5 minutes. Add chicken stock and bring to a boil. Reduce heat to a simmer and add cauliflower, clams, shrimp, bacon, and seafood spice. Simmer gently for 15 minutes. Add asparagus and simmer until just tender, about 5 minutes more.

Divide chowder between 2 soup bowls and add cream to each. Season with salt and pepper.