Wash the leeks and slice them finely.

Sauté the chopped onion with butter in a frying pan over low heat, stirring occasionally. The onions should not brown but remain white.

Add the leeks and mix well. Cover and cook for about twenty minutes.

Add the cream just before serving. You can keep the cooked leeks aside until ready to serve, then add the cream.

Let it reduce for about ten minutes, depending on the desired consistency. The fondue will thicken slightly as it cools.

Meanwhile, when the leek fondue is almost ready, cook the salmon steaks.

Heat a non-stick frying pan. When hot, place the salmon steaks skin-side up (the pink flesh side down) in the pan. Cook for 30 seconds on high heat, then carefully turn them over. The cooking is done without any added fat.

Let them cook skin-side down until the sides take on a uniform color.

At the end of cooking, carefully flip the salmon one last time and gently remove the skin.

Serve immediately !