- In a saucepan over medium heat, brown the shallot in 15 ml (1 tablespoon) oil. Season with salt and pepper. Add the pineapple and continue cooking for 4 to 5 minutes. Deglaze with the vinegar. Transfer to a blender, add 60 ml (1/4 cup) oil and purée until smooth. Adjust the seasoning. Pour into a small saucepan and set aside over low heat.
- Fill a large saucepan with water and heat until it starts to simmer.
- Season the fish with salt and pepper. Place each piece in a bag. Seal partially and squeeze out as much air as possible. Seal tightly.
- Place the bags in the water and cook over low heat for about 12 minutes.
- Serve the fish with the pineapple sauce.