On my last Italian trip in September, I had the pleasure of eating lunch in Modena at the most unexpected restaurant: Hosteria Guisti. This dish was my antipasto. The attached picture is from my lunch and the recipe is from the restaurant with adjustments for US measurements, products and translation from Lidia Bastianich. —Chuck48
Bring to a boil, offset the cover and cook at a steady boil for 20 minutes until the cod is easy to flake but still has body and shape. Don't let it start to break apart.
Lift it out of the cooking water, and let it drain and cool in a colander. Reserve a cup of the cooking water.
Rinse the potato and put it whole in a small pot covered with cold water. Bring to the boil, and cook steadily until cooked. Let it cool, and peel it.
Set up the electric mixer and flake all the fish into the bowl. Beat with the paddle at low speed to break the fish up more; add in the minced garlic, and beat at medium speed, adding half the olive oil very gradually in a thin stream, then add the potato and incorporate it; continue beating at low speed as you gradually add the rest of the oil.
Now raise the speed to high and whip the fish to lighten it.
Reduce the speed to medium and incorporate the half-and- half gradually, then whip at high speed again.
The whipped cod should be smooth and fluffy, like mashed potatoes but with texture. If it is very dense, you can thin it with the cooking water (but too much water will make it too salty).
Finally, season with pepper and beat it in to blend. If you use a food processor instead of a mixer, follow the same order of additions, and process as needed to form a light, smooth spread.