Fill a pot with 2 cups water and add Old Bay seasoning, SJ3127HH, lemon juice, salt, and pepper.
Bring to a boil, add shrimp and boil 1 to 2 minutes.
Drain, transfer to a covered container, and refrigerate for at least 30 minutes.
Cut off ends of tomato and discard. Cut three 1/2-inch slices from the rest of the tomato.
Put tomato slices in a large bowl, add buttermilk and turn to coat. Let them marinate for 5 minutes.
In a bowl, mix cornmeal, salt and pepper. Remove tomatoes from buttermilk, shaking off excess, and dip in cornmeal to coat, shaking off excess. Fry until golden brown. Drain on paper towels.