Combine spice mix ingredients in a small bowl. Toss peeled shrimp with 1/2 spice mix and set aside.
Heat oil in a heavy-bottomed saucepan over medium heat until shimmering. Add onion and saute until soft, about 2-3 minutes. Add minced garlic and saute until fragrant, about another minute.
Add shrimp shells, bay leaves, rosemary, lemon, water, coffee, Worcestershire sauce, and reserved spice mix. Simmer 30 minutes.
Strain shrimp peel liquid through a fine mesh strainer into a measuring cup. You should have about 2 cups of broth.
Return broth to the saucepan and boil until reduced to 1-1/2 cups, about 15 minutes. Stir in heavy cream and brown sugar. Simmer another 5 minutes.
Add shrimp to sauce and boil until just cooked through, about 2-4 minutes.Using a slotted spoon, transfer shrimp to a bowl. Stir in well-drained diced tomato, butter, basil and parsley into sauce. Adjust seasoning to taste.
Serve over polenta, grits, garlic mashed potatoes or toasted cornbread wedges. Garnish with additional chopped parsley, if desired.