Degree of difficulty: 3
Cut 5″/14 cm lengths from the carrots and celery; save the trimmings. Peel one of the onions and cut in half; reserve the onion trimmings as well.
Cut the trimmings coarsely into small pieces. Cut the whole remaining onion into small pieces and combine with the chopped vegetables; set aside.
Peel the potato, cut it in half and stage into a dedicated vacuumed bag as shown above. Seal the onion halves and the carrot/celery sections into another vacuum bag. Stage the beef shanks into a vacuum bag. If you want to use self sealing/Ziploc gallon freezer bags, remove the air from the bags using the water displacement method. Set the shanks aside.
Preheat the sous vide bath to
Put the sealed packages of vegetables and potatoes–not the shanks–in the sous vide bath. If the bags float, put an upside down rack on top of them. Process the vacuumed vegetables and potatoes for 1 hour. When the time has elapsed, plunge the bags into iced water until they achieve 70F/21C. Refrigerate at 40F/4C.
Lower the temperature of the bath to
Put the beef shanks in the sous vide bath. Note the time or set the timer to 24 hours.
Make the sofrito broth
While the shanks are processing, heat a skillet to 225 F/107 C. Add 2 oz/50 ml vegetable oil and fry the trimmings of the carrots, celery and onions until they are very brown–avoid stirring. This should take about one hour. The oil must cover the bottom of the pan. It may seem somewhat “greasy; the excess fat will be removed later.
Add the tomato paste and stir until it coats all of the vegetables.
Continue frying until the tomato paste browns–it will start to stick to the bottom of the pan–scrape periodically with a wooden spoon. This will take about fifteen minutes. Remove the vegetables from the pan and put them on a clean towel or paper towel to absorb the excess oil. Do not clean the pan–add 1 quart/1 liter of water, bring to a boil, add the drained vegetables, return to boil and remove from heat. Set aside to cool somewhat.
Transfer this sofrito broth to a Ziploc gallon freezer bag but do not seal. Lower the bag slowly into the same sous vide bath as the shanks and drape the opening over the edge of the vessel. Use a clothespin or vessel lid to secure the bag.
Bring 2 cups water to a rolling boil with a pinch of salt. Pour the boiling water over the green beans and let sit for five minutes. Drain the water and replace with cold water. Allow to sit long enough to cool, drain, refrigerate at 40F/4C..
When the 24 hours has elapsed, reduce the heat in the bath to 130F/54C. At this temperature the shanks and sofrito broth can be held up to 12 hours without affecting quality. At service, remove the package with the shanks, place it in a large bowl and cut open the bag. Remove the shanks and set aside. Transfer the juices to a microwaveable container and process (in the microwave) for 30 seconds.
Put a paper towel or coffee filter in a strainer and pour the microwaved juices through it into a sauce pan. Remove the bag with the sofrito broth and strain into the same pan. Bring to a simmer and test for salt to your liking. Cut open the bags with the celery/carrot/onion sections and the potatoes and stage into the clear broth. Pat the shanks dry, add to the pan and bring just to a simmer–do not boil. Put the shanks in the serving dish, arrange the vegetables around them and pour the broth over it.
Garnish with the fresh herbs and serve.
For an alternate presentation, use the point of a knife to carefully break apart the shanks, cut the vegetables and potatoes into a few pieces, and serve like this: