At least 36 to 60 hours before serving
Preheat a water bath to 131°F (55°C).
Mix together the spices in a bowl. Lightly salt the steak then coat with the spices. Place the steak in a sous vide bag then seal. Cook the steak for 36 to 60 hours.
At least 20 minutes before serving
Combine all the ingredients into a blender or food processor and process until it forms a smooth paste. This can be done a day or two ahead of time and stored in the refrigerator.
20 minutes before serving
Fill a pot of oil one third to half way full with oil then heat it to 350°F (176°C). Set up a plate with paper towels on it or a cooling rack over a baking sheet.
Add the brussels sprouts to the hot oil, working in batches if necessary to prevent overcrowding. Cook them until golden brown, 2 to 4 minutes. Remove from the heat and place on the cooling rack. Sprinkle with salt and pepper.
Remove the cooked steak from the sous vide bag and pat dry. Lightly salt the outside of the steak then quickly sear it until the meat is just browned. Cut into thick slices.
Place the steak on a plate with the brussels sprouts. Top the brussels sprouts with the blue cheese crumbles. Add a dollop of pesto to the steak then top with the basil leaves and lemon zest. Drizzle some lemon juice over the brussels sprouts then serve.
For a fun plating change I like to make browned butter balls to serve on the brussels sprouts. Melt 150 grams butter over medium heat and lightly whisk it as it melts. The butter will begin to foam and once it settles the milk solids will start to brown. Once the butter begins to brown and smell nutty, remove it from the heat. The butter can very quickly go from browned to burned so keep an eye on it.
Let the butter cool slightly then slowly whisk or stir in enough maltodextrin for it to form a thick paste that you can easily form into balls. It usually takes around 70 to 100 grams.
Form the butter paste into small balls about 1/2" (13mm) in diameter. Once made, the butter balls can stay in the fridge for several days.