Peel the lemons, using a potato peeler, making sure not to remove any of the white pith. This should yield about 1 cup of lemon peel. Save the peeled lemons for juice in other dishes.
Place the peel in a mortar along with 1/4 cup of the olive oil. With the pestle, pound and rub the peel and oil together for one minute.
Remove to a 2 quart glass jar or sealed plastic container and add the remaining 3 3/4 cups of olive oil. Allow to marinate four days at room temperature.