Preheat to oven to 425°F and line a large baking sheet with foil. Cook the frozen fries according to the package directions.
Heat a large skillet over medium heat and add the diced bacon. Cook until crispy and rendered. Remove the bacon from the pan and reserve for later.
To the drippings in the pan, add the sliced onion and minced garlic. Cook until starting to soften and then reduce the heat to low. Cook, stirring frequently, for 15 minutes or until the onions are caramelized and soft. Set aside.
To the cooked fries, add the caramelized onions, spreading them out as evenly as possible.
Add the bacon, scallions, and shredded cheeses.
Return the fries to the oven and cook for a few minutes or until the cheese is melted. Garnish with the scallions and serve with the gravy drizzled over top or on the side as a dipping sauce.
For the Gravy:
While your fries are cooking and your onions are caramelizing, melt the butter over medium heat in a medium saucepan. Whisk in the flour and cook for a couple minutes.
Slowly stream in the stock and bring to a gentle simmer, stirring constantly. Add in the whiskey and continue to cook and stir until the mixture is thickened and slightly reduced, about 5 minutes.
Season, to taste, with salt and pepper. Keep warm until you are ready to serve.