Season the halibut with salt and pepper.
Place it in a vacuum bag and remove the air using a vacuum sealer.
Place the bag and sous vide runner in a pot or container full of water and set it to cook at 140ºF for 1 hour.
Remove the halibut from the bag and dry it with paper towels.
Heat a non-stick skillet to medium-high heat, add 1 tbsp. olive oil, and cook the halibut for a minute or so until browned on both sides. Set aside.
Melt the butter in the same pan over medium heat until foaming. Add capers and cook, stirring, for 2 minutes or until butter starts to brown lightly.
Add lemon juice. Cook, stirring, for 1 minute. Remove from heat. Stir in parsley. Season with salt and pepper.
Serve the halibut with the lemon caper sauce on top.
