Rinse frog legs and pat dry. Separate the legs at the joint if desired. Set aside. In a medium bowl, mix together 1 cup milk, half of the beaten egg (about 1 tablespoon), garlic powder, and onion powder. Place the frog legs into the mixture, cover and refrigerate for about one hour, stirring occasionally.

In a large bowl, stir together 1 cup flour, bread crumbs, cornmeal, baking powder, 2 teaspoons salt, 1 teaspoon pepper, cayenne, paprika, oregano, thyme, cumin and parsley. Mix well and set aside.

Heat the olive oil and butter in a large skillet or electric skillet set to medium heat. For an electric skillet, set to 325 degrees F (165 degrees C). Dip each frog leg portion into the flour and spice mixture, packing on as much of the dry mixture as you can. Place the coated frog legs into the pan so they are close but not touching. Cook for about 15 minutes, until browned and crispy, turning often to prevent burning. Take care, they will become more fragile as they cook. Remove from pan, and place on paper towels to drain.

Add the chopped onion and mushrooms to the skillet, and sprinkle them with chicken bouillon. Cook, stirring frequently until onions and vegetables are soft. Sprinkle the last 2 tablespoons of flour into the skillet, and stir to blend in. Cook, stirring constantly until the flour is browned. Mix together the remaining 1 cup milk, evaporated milk, and the other half of the beaten egg. Gradually mix into the skillet. Whisk or stir constantly until the gravy is thick and bubbly. Season to taste with salt and pepper. Add the frog legs, and serve them smothered with gravy.