Wash the roe well; then put it into a saucepan on the fire, well covered with salted water, to which has been added a little lemon-juice or vinegar. Boil for ten minutes; drain, and leave it to get cold; then cut the roe into slices a quarter of an inch thick, dip the slices of roe into batter, and fry in butter until of a light brown color. Serve, garnished with fried parsley and with slices of lemon. Batter: Beat up together the yolks of two eggs, one tablespoonful of olive oil, and four or five tablespoon-fuls of cold water; amalgamate with this three tablespoonfuls of fine flour, and a good pinch of salt; beat the mixture five or ten minutes, adding a little more water, if too thick. Just before using it, stir into it lightly and quickly, the whites of two eggs whisked to a froth.