In a large mixing bowl, beat the eggs together with yeast and water. Add the flour and mix the batter with a fork by hand until it looks like the consistency of a thick pancake batter. If needed, add a couple more tablespoons of flour, one at a time. The batter should be thick enough to coat the fish.
Cover the mixing bowl with plastic wrap and leave to rise in a warm place for about 1 to 2 hours, or until small air bubbles form on the top of the batter. This batter takes longer to rise than most recipes that use dry active yeast because of the addition of the eggs, which weighs the batter down.
Rinse the cod for a last time; dry it well and cut into small pieces. The batter will expand and puff up when fried, so keep the baccalà pieces small, about 3/4-inch.
Drop a handful at a time of baccalà pieces into the batter, allowing the excess to drip off just slightly remove them from the batter and gently drop the pieces in the oil and cook until golden brown and crisp, about 5 minutes.
Remove the fish from the oil, briefly drain on a plate lined with paper towels. Serve with warmed marinara sauce, lemon wedges, or cocktail sauce.