Step 1

To make the tare: Combine mirin, soy sauce, sake, brown sugar, sherry vinegar, garlic, scallions, ginger slices, and peppercorns in a medium saucepan. Bring to boil over high heat, then reduce to a simmer, whisk to combine, and cook until mixture is thick and syrupy, about 45 minutes. Strain through a fine mesh strainer. Set aside or store in an airtight container in the refrigerator until ready to use.

Step 2

To make the mochi: Cut mochi into blocks roughly 1 1/2-inches by 3/4-inch. Wrap a halved bacon slice around each piece of mochi.

Step 3

Light one chimney full of charcoal. When all the charcoal is lit and covered with gray ash, pour out and arrange the coals on one side of the charcoal grate. Set cooking grate in place, cover grill and allow to preheat for 5 minutes. Clean and oil the grilling grate. Place mochi on cool side of the grill, cover, and cook until bacon has browned and mochi has softened, 15-20 minutes. Brush mochi with tare sauce all over, cover grill, and continue to cook for about 2 minutes. Remove mochi from grill and serve immediately.