Heat oven to 325° F.
4 pound top round roast
1 1/4 teaspoons salt, divided
1 tablespoon peeled and thinly sliced garlic
1 tablespoon dried oregano
1 tablespoon dried thyme
2 teaspoons dried rosemary
1 teaspoon freshly ground black pepper
1 teaspoon dry mustard
2 teaspoons neutral oil, divided
1 large peeled and diced onion
Flat Italian leaf parsley
Cut slits deep enough to enclose the slices of garlic in the top of the roast and slip a slice of garlic into each slit.
Liberally cover both sides of the roast with 1 teaspoon salt.
Place on rack over a plate and chill 24 hours, uncovered.
The next day, allow roast to rest on the counter for 1 hour (to come to room temperature) before beginning cooking process.
Heat a cast iron skillet, large enough to hold the roast, over medium heat.
When hot, add 1 teaspoon oil.
When oil shimmers, add onion slices.
Sprinkle onions with 1/4 teaspoon salt.
Saute until translucent, but not brown.
Place onion in bottom of roasting pan.
Place oregano, thyme, and rosemary in a mortar and grind with a pestle.
Add pepper and dry mustard.
Heat the large cast iron skillet over medium-high heat.
Place 1 teaspoon oil in hot cast iron skillet.
When oil shimmers, place roast in skillet.
Sear for 2 – 3 minutes or until the bottom is brown and crusty.
Turn with a tong.
Sear this side 2 – 3 minutes or until this side is nicely browned and crusty.
Turn roast on each edge and sear until crusty, 2 – 3 minutes per edge.
Sprinkle side of roast without garlic slits with herb mixture.
Place roast, with side of roast without garlic slits down, on top of the onion.
Sprinkle herb mixture over the top (side with garlic slits) of the roast.
Pat sides of roast with herb mixture.
Sprinkle any remaining herbs over the onions.
Place roast in oven. Roast approximately 1 1/2 hours for medium-rare doneness (120 – 130° F).
Remove roast from oven, tent loosely with tin foil and allow to rest 15 minutes (the roast will continue to cook an additional 10 – 15° F).