Whisk the mirin, and soy together along with the 2 cloves of minced garlic.
For the roast:
Using a butcher knife, penetrate the roast. (Spread the holes evenly around the roast.) Insert a sliced garlic clove deep into each penetration. Place into a large bowl and rub the roast with a light coating of olive oil. Salt and pepper the entire roast evenly. Pour the garlic Teriyaki sauce over the roast. Roll the roast around in the garlic Teriyaki. (try to make sure that the garlic teriyaki gets deep into the penetrations in the roast as well). Let the roast marinate over night.
Adjust rotisserie coals for indirect heat.
Tie down the roast on your rotisserie, and discard marinate. This should preheat to 375 degrees F to char the outside and then cook at 350 degrees F or about an hour. This roast should be served medium rare.
All recipes require charcoal for best results.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.