Dice the onion, celery, leek and bell pepper into small pieces.
Melt one Tablespoon of the butter in a large stock pot and sauté the vegetables.
While veggies are cooking, get all the liquids ready, clam juice, chicken broth and sherry wine. Add to the sautéed vegetables with potatoes. Also add all the spices. Bring this back to a boil. Put the lid on and leave a small crack for the steam to escape. Reduce the heat to a simmer, but make sure everything is still boiling for 30 minutes.
Add the rest of the butter in a shallow baking dish and put in a 325° oven. When melted add the flour and stir. Cook this flour mixture for 30 minutes in the oven.
Pour the flour mixture into the chowder, stirring continually. Your chowder will be very thick.
Add the heavy cream, clams and hot sauce. Stir until all ingredients are well mixed. Put the lid on and cook on low for 10 minutes.