Johnny Spero’s Sweetbreads

1. Bring the water to boiling; add vinegar.
2. Using a fine mesh spoon, place the sweetbreads in boiling vinegar water. Blanch for 5 seconds, then remove and immediately place in the refrigerator.
3. After cooling for about 5-10 minutes, peel the sinew from sweetbreads. Place the sweetbreads in the pouch with the shio koji. Vacuum seal.
4. Set circulator in water bath to 176°F (80°C) for 20 minutes.
5. After 20 minutes, remove the sealed pouch from the water bath and allow to cool at room temperature for 10-15 minutes.
6. Once cool, cut open the pouch and pour off the excess liquid. Pat the sweetbreads dry.
7. In a very hot nonstick pan, gently brown the sweetbreads on one side until a golden crust has been achieved. Then drop heat to medium/medium-high to cook a few minutes longer, about 3 minutes. Flip gently and repeat on the other side.
8. With heat at medium/medium-high, add the lamb or beef stock and slowly glaze the pan and the sweetbreads on both sides, using a curved spatula to stir as the stock reduces. As stock thickens, add butter. The stock will become very thick as it reduces, leaving almost an entirely dry pan with the majority of the sauce sticking to the meat.
9. Turn off heat. Remove the sweetbreads from the pan and place on a cutting board. Allow to rest briefly.
10. Slice into 1-inch-thick slices and serve with extra pan glaze and a light sprinkle of flaky salt.

Developed by Johnny Spero, and shared with Sous-Vide magazine.