Make the yeast mixture: Combine yeast, 1/2 cup warm water, and 1 tsp. granulated sugar in bowl of a heavy-duty stand mixer; let stand 5 minutes. Add milk, eggs, salt, and remaining granulated sugar.
Form a dough: Microwave remaining 1 cup water until hot (about 115°); stir in shortening until melted. Add to yeast mixture. Beat at low speed, gradually adding 4 cups flour, until smooth. Gradually add remaining 2 1/2 to 3 cups flour, beating until a sticky dough forms. Transfer to a lightly greased bowl; turn to grease top. Cover and chill 4 to 24 hours.
Roll and cut: Turn dough out onto a floured surface; roll to 1/4-inch thickness. Cut into 2 1/2-inch squares.
Fry until golden: Pour oil to depth of 2 to 3 inches into a Dutch oven; heat to 360°. Fry dough, in batches, 2 to 3 minutes on each side or until golden brown. Drain on a wire rack. Dust immediately with powdered sugar.
6(8- to 10-ounce)fish filletspreferably redfish substitute with bass cut about 1/2 inch thick
Heat a large cast-iron skillet over very high heat until it is beyond the smoking stage and you see white ash in the skillet bottom (the skillet cannot be too hot for this dish), at least 10 minutes.
Meanwhile, pour 2 tablespoons melted butter in each of 6 small ramekins; set aside and keep warm. Reserve* the remaining butter in its skillet. Heat the serving plates in a 250-degree oven.
Thoroughly combine seasoning mix ingredients in a small bowl, Dip each fillet in the reserved melted butter so that both sides are well coated; then sprinkle seasoning mix generously and evenly on both sides of the fillets, patting it in by hand. Place fish in the hot skillet and pour 1 teaspoon melted butter on top of each fillet (be careful, as the butter may flame up)
For the fried shrimp:
Preheat oil in fryer to 360 degrees.
Season the shrimp with salt and pepper.
Season the flour with salt and pepper. Dredge the shrimp in the flour.
Make an egg wash with the egg and the water. Dredge the shrimp in the egg wash. Dredge the shrimp in the cornmeal. Fry the shrimp until golden brown. Drain on a paper towel lined plate to get rid of excess oil.
To assemble: Slice the French bread and toast lightly in oven. Spread mayo and place lettuce, and tomatoes on the bread. Place fried shrimp on bottom bun.