Check to be sure that all the internals have been removed and rinse the fish.
Pre-heat the oven to 425°.
Slice 3 of your lemons into rounds and set aside.
Chop the basil and set aside.
Put the salt in large bowl and add the egg whites mixing the salt till it resembles wet beach sand. Add water if needed but do so sparingly only adding as much as needed to keep the salt coarse.
On a cooking sheet, that is large enough to hold the fish, place a layer of parchment paper then spread a layer of salt about 1/2 inch thick. If you can use a sheet that has 1/2 inch high sides.
Spread the chopped basil evenly inside the cavity of your fish.
Fill the cavity with the lemon rounds.
Place the fish on the salt covered cooking sheet
Take the lemon rounds and stuff the cavity with them.
Take the remaining salt and spread evenly over the fish, about 1/2 inch thick, covering the head and tail last if you want.
Cook for 35 minutes and check the temp of the fish. You are looking for an internal temp of around 165° when checked with an instant read thermometer. If it is not at that temp cook a little longer. Remove from oven when desired temp is reached and allow to sit for 10 minutes.
Using a wooden spoon strike the hardened salt till it cracks and remove the pieces from the fish being careful not to allow much to filter into the fish.
Once the top layer of salt has been removed transfer the whole fish off the cooking sheet and onto a platter and filet to remove the bones.
Recipe by From Calculu∫ to Cupcake∫ at https://www.fromcalculustocupcakes.com/italian-salt-fish/