Preheat oven to 425°F. Line a large baking sheet with parchment and set aside.
Scrub the potatoes under running water and place on a work surface. Cut away any blemishes. Then cut the potatoes into halves. Cut each half lengthwise into halves again. Then cut each quarter into two wedges. Place the potatoes in a mixing bowl and toss with the oil until coated evenly.
Scatter the potatoes evenly across the prepared baking sheet in a single layer. Bake until golden and tender, about 20 to 30 minutes, giving them a shake halfway through for even browning. You can also prepare the sauce and toppings while the fries are baking.
Stir the buffalo wing sauce and ranch together in a small saucepan over medium-low heat. As soon as it bubbles, reduce heat to the lowest setting to keep warm and reserve.
Remove the potatoes from the oven and transfer to a rectangular ovenproof pan. Turn on the broiler.
Drizzle the wing sauce evenly across the potatoes. Sprinkle the cheddar cheese on top followed by the crumbled gorgonzola/blue cheese.
Put the pan into the oven to broil for 2 to 4 minutes, or just until the cheese is starting to bubble. (Note: If your broiler is weak, you may need to move the oven rack higher so the fries are about 3 inches from the broiler.)
Remove the buffalo fries from the oven. Garnish with green onions and serve warm.