Cut the garlic in slices, enough to cover the whole salmon.
Spread the oil to cover the entire fish.
Spread the kosher salt on the fish.
arrange a layer of garlic slice covering the entire fish.
In an oven dish, place the rosemary branches in a thin layer (if using).
Carefully place the salmon with the garlic facing down. Some garlic slices will fall, but most will stick to the fish due to the oil.
pour the wine to cover up to at least half the fish height.
Put the fish in an oven preheated to 180°C (360°F) for 35 minutes. Don't let it stay there more as the salmon will dry up. If the fillet is thinner, take it out even at 30 minutes.
Times may vary from oven to oven, try adjusting from time to time. Also, frozen fish will tend to be drier, use fresh when possible.
When ready, take out of the oven and serve immediately, use a spatula to take the salmon out, keeping as much of the garlic slices as possible. Fish out fallen slices and put on the served fish. Throw away the rosemary.