In a large bowl, combine the freshly ground beef, Steakhouse Onion Burger Seasoning, and grated garlic. Divide the meat into four portions. Using the Napoleon Gourmet Burger Press, form four delicious patties. Chill them for 25 minutes while you prep the grill and everything else.
Preheat your grill to 350°F. Place a cast iron griddle directly on your cooking grids over direct heat or replace your cooking grids with the cast iron griddle. (The size of griddle you have depends on the size of your grill) Brush the griddle with your favorite high-heat oil like peanut, coconut, or avocado.
While the grill is preheating, place a saucepan over low heat. You can do this on your side burner or on your stovetop. Melt the butter and whisk in the mustard, garlic, and onion powder. Whisk in the flour. In a measuring cup combine the stock, sake, and soy. About ¼ cup at a time, add the stock mixture until you have reached your perfect gravy consistency – smooth, coats the back of your spoon – then whisk in the miso paste, Worcestershire, and add pepper to taste. Keep warm.
When the grill is hot, toss down 1 tbsp. of butter and add the onions to one end of the cast iron griddle, then place the burgers on the grill to cook over direct, low heat. At this temperature, the onions are going to fry more than caramelize. Start them sooner at a lower temperature if you want your onions caramelized.
After about 7 or 8 minutes, flip the burgers, wait about 2 minutes and then drop the remaining tablespoon of butter. Spread it around and then fry your eggs until the white has set. About 3 minutes.
Serve everything together. Lay down a bed of rice, place the burger patty on top, followed by the egg. Garnish with Hawaiian black salt and chives.