Larding and Marinating
Pierce channels entirely through the grain of the beef roast using a narrow knife. Insert the frozen bacon strips firmly into the paths. Season the exterior with salt and pepper. Place the beef in a container surrounded by the raw chopped carrots, celeriac, parsley root, onions, and the spice sachet. Drizzle with 2 tablespoons of vinegar, cover, and refrigerate overnight.
Freezing the bacon keeps it from crumpling. The overnight marination allows the vinegar and aromatics to tenderize the muscle fibers.
Uniform plugs of fat cleanly embedded throughout the meat.