Pour the peanut oil in a Dutch oven until it reaches about 2 inches or so deep.
Heat on med/hi heat to 375 degrees F.
If needed, separate the legs with a sharp knife.
Place one cup of the flour in a medium bowl.
Whisk the egg and milk together in a separate medium bowl.
Combine the rest of the flour, the cornmeal and the Cajun spice in a third medium bowl.
Coat the frog legs with flour from the first bowl and place on a wire rack to rest for five minutes.
Dip the frog legs in the egg mixture to coat.
Dip the egg coated frog legs into the flour/cornmeal mixture and cover well.
Working in batches of 5-7 single frog legs, place the frog legs into the hot oil and fry 4-5 minutes. Turn them over and fry another 5-6 minutes. The frog legs will float when they're done.
Place the cooked frog legs on a paper towel covered plate to drain excess oil and sprinkle with salt as desired.
Finish cooking the rest of the frog legs and serve hot.