Heat oil in a large pot or deep fryer to 325°F. Fry the cut potatoes in batches for 5 minutes until soft but not browned. Remove and drain on paper towels.
Increase oil temperature to 375°F. Fry the potatoes again in batches for 3-4 minutes until golden brown and crispy. Drain and season immediately with salt and pepper.
Arrange the hot fries on a large oven-safe platter or baking sheet. Drizzle the warm cheese sauce over the fries.
Sprinkle shredded cheddar cheese and crumbled bacon over the top. Place under the broiler for 1-2 minutes until the cheese melts.
Remove from oven and top with dollops of sour cream, green onions, and jalapeño slices if desired. Serve immediately while hot.