Cover brains with cold water, add vinegar, and soak for 30 minutes. Drain. Remove loose fatty membrane. Cover brains with water, add 1/2 teaspoon salt, and simmer 20 to 30 minutes. Drain and chill in cold water. Finely chop brains. Brown in butter. Combine eggs, milk, and 1/4 teaspoon salt. Add to brains. Turn heat low. Don't disturb mixture until it starts to set on bottom and sides, then lift and fold over with wide spatula so uncooked part goes to bottom. Avoid breaking up eggs any more than necessary. Continue cooking 5 to 8 minutes, until eggs are cooked throughout, but still glossy and moist. Remove from heat and serve immediately.
Cover fresh brain with salted cold water for 1/2 hour. Drain. Chill then slice and season to taste. Roll in beaten egg and cracker crumbs. Fry in hot butter or lard until golden brown.