Slice the tomatoes 1/4-inch thick. Lay them out in a shallow baking pan and sprinkle with salt. Place the tomato slices in a colander and allow time for the salt to pull the water out of the tomatoes, approximately 30 minutes. In a skillet, heat the oil for deep-frying over medium-high heat. Dip the tomatoes into buttermilk, then dredge them in flour. Deep-fry until golden brown. Keep warm.
Meanwhile, prepare Hollandaise Sauce.
To assemble each serving, place 2 fried tomatoes on a plate. Top with 2 strips of cooked bacon in a criss-cross fashion. Top bacon with a poached egg, spoon on Hollandaise Sauce.
Combine all ingredients in the top of a double boiler, over boiling water. Stir until thick, approximately 3 minutes; set aside until ready to use. Do not reheat or cover the pot. Thin, if needed with a little chicken broth. Stir in the vinegar. Use immediately.