Mix until combined and the oil just covers the garlic, adding more oil as necessary. Cook over medium heat until the oil begins to bubble and the garlic turns golden brown, 2 to 3 minutes. Immediately remove from the heat and drain off the oil. Set the garlic aside and let cool.
Combine the pear puree, sugar, soy sauce, oyster sauce, rice wine, pepper, schichimi togarashi and 5-spice powder in a 2-quart saucepan and mix thoroughly with a whisk. Cook over high heat until the mixture comes to a boil.
Add the prepared garlic mixture, lower the heat and simmer until slightly thickened, about 15 minutes.
Remove from the heat and stir in the onion and scallion.
Let cool to room temperature, about 30 minutes.
Meanwhile, remove any excess fat and sinew from the ribs.
Cut into 1/2-inch cubes and transfer to a 4-quart container.
Slowly pour the cooled BBQ marinade over the ribs and mix until thoroughly coated. Marinate the ribs in the refrigerator at least 8 hours.
Drain the ribs and onion of excess BBQ marinade through a sieve or strainer.
Heat the oil in a frying pan over high heat, 2 to 3 minutes.
Add the ribs and onion and cook, mixing often to prevent burning, until caramelized and cooked to desired doneness, 2 to 3 minutes for medium-rare, 3 to 5 minutes for medium.
