Steak Tartare

Steps

1. 1Cut the steak into 1-inch cubes and park in the freezer for 10 minutes.
2. 2Whisk the vinegar, dry mustard, and egg yolks together in a small bowl. Whisk continuously while streaming in the oil until emulsified, then whisk in the shallots, capers, salt, and roughly 2/3 of the celery leaves and parsley.
3. 3Hand chop the meat to your desired texture. Alternately, divide the meat into 4 batches and pulse each batch separately 3 to 4 times in the bowl of a food processor fitted with the standard S-blade.
4. 4With clean hands, quickly fold the meat and dressing together. Plate using a 3 3/4-inch pastry ring and garnish with the reserved herbs and lemon zest.