Place the tenderloins in a gallon-sized freezer food storage bag. In a bowl combine 2 tablespoons of the vegetable oil and the remaining ingredients and whisk to combine. Pour the marinade over the tenderloins, seal the bag, and move the tenderloins around in the marinade so that they are evenly coated. Refrigerate the tenderloins, turning occasionally, for at least 4 hours and up to overnight.

When you are ready to cook the tenderloins, remove them from the refrigerator at least an hour before you plan to cook them and allow them to come to room temperature. Preheat your sous vide waterbath to 57 degrees C.

Seal the bag with the tenderloins so that there is no air remaining, then lower the bag into the water bath. Cook the tenderloins for 1 1/2 hours for medium, or longer if desired. Remove them from the water bath and discard the marinade and any accumulated cooking juices from the bag. Heat a large nonstick skillet and add the remaining 2 tablespoons vegetable oil. When hot, add the tenderloins and cook, turning as necessary, until nicely browned on all sides, 4 to 6 minutes. Transfer the tenderloins to a cutting board to rest at least 5 minutes, then slice on the diagonal to serve.

Serve with rice or noodles alongside pickled vegetables, garnished with fresh herbs and drizzled with nuoc cham if desired.