Step 1

Add the rosemary, the thyme, and the fennel seed to a mortar bowl and use the pestle to break them up until they are partially ground, but still recognizable.

Step 2

Melt the butter in a large stockpot over low heat.

Step 3

Add the tomato paste to the butter and cook until it loosens.

Step 4

Add the spice mixture, the celery seed, the garlic, the crushed red pepper flakes, and the clam broth to the tomato paste mixture and cook, about 1 hour.

Step 5

Add the shrimp to the broth mixture and simmer, stirring regularly, until they are plump and cooked through, about 2 minutes.

Step 6

Serve the shrimp in bowls with enough of the broth to completely cover them.