In a large pot over medium heat, melt the butter. Sauté the onion and garlic until soft, 2 to 4 minutes. Sprinkle the potato starch over the vegetables and whisk in the broth until combined with no lumps.
Add the tomato paste, Worcestershire sauce, Old Bay, and cayenne pepper, and stir to combine. Reduce the heat to
low, and add the heavy cream.
Gently add in the crabmeat, being careful not to completely break up the chunks of meat. Simmer for 5 minutes, or until heated through. Season with the salt and pepper.