Place the pre-soaked salt cod in a large saucepan and cover with cold water. Add the bay leaf and bring to a gentle simmer over medium heat.

Poach the cod for 20-25 minutes until it flakes easily and reaches an internal temperature of 63°C. Remove from water and let cool slightly.

While cod poaches, bring 500ml salted water to a boil. Slowly whisk in the polenta and cook for 5 minutes, stirring constantly until thick.

Stir rosemary into the polenta, then pour into a lined 20x20cm baking dish. Spread evenly to about 1.5cm thickness and refrigerate for 20 minutes until firm.

Remove all skin and bones from the poached cod, then flake the flesh into a large bowl or stand mixer fitted with the paddle attachment.

Add minced garlic to the cod and begin whipping on medium speed. Very slowly drizzle in the olive oil in a thin stream, whipping continuously for 8-10 minutes until light and fluffy.

Fold in the lemon juice and chopped parsley. Season with black pepper to taste. The mixture should be smooth and spreadable.

Cut the chilled polenta into 12 squares or triangles. Brush both sides lightly with olive oil.

Heat a grill pan or griddle over high heat. Grill polenta pieces for 3-4 minutes per side until golden char marks appear and edges are crispy.

To serve, place warm polenta crostini on a platter and top each generously with whipped baccalà mantecato. Garnish with fresh chives and lemon zest.