Step 1: Cook the Bacon
You can cook your bacon using your preferred method: pan-frying on the stove, baking in the oven, or even in the air fryer before you cook the fries. The goal is to render it nice and crispy. Once cooked, transfer the bacon to a paper towel-lined plate to drain excess grease, then crumble or chop it into bite-sized pieces. Set aside.

Step 2: Make the Velvety Cheese Sauce
In a medium saucepan over medium heat, melt the butter. Once the butter is melted and foaming, whisk in the all-purpose flour. Cook, whisking constantly, for about 1 minute. This step cooks out the raw flour taste and creates the roux.
Slowly pour in the warmed whole milk and the evaporated milk, whisking vigorously and constantly to prevent any lumps from forming. Continue to cook, stirring frequently, for 4-5 minutes, until the sauce has thickened enough to coat the back of a spoon.
Reduce the heat to low. Add the smoked paprika, garlic powder, mustard powder, and cayenne (if using). Stir to combine.
Begin adding the freshly grated cheddar cheese a handful at a time, stirring until each addition is completely melted and smooth before adding the next. This gradual process is key to a non-greasy, perfectly smooth sauce.
Once all the cheese is incorporated, remove the sauce from the heat. Taste and season with salt and black pepper as needed. Keep the sauce warm over very low heat while the fries cook.

Step 3: Air Fry the Waffle Fries to Crispy Perfection
Preheat your air fryer to 400°F (200°C) for about 3-5 minutes.
Place the frozen waffle fries in the air fryer basket. It’s okay if they overlap a bit, but do not fill the basket more than halfway to ensure proper air circulation.
Air fry for 12-15 minutes, shaking the basket vigorously or tossing the fries with tongs halfway through the cooking time. This is crucial for even browning and crisping. The fries are done when they are golden-brown, crispy on the edges, and cooked through. Cook time may vary slightly depending on your air fryer model.

Step 4: Assemble Your Masterpiece
Once the fries are perfectly crispy, immediately transfer them to a large platter or serving dish, spreading them out in a relatively even layer.
Drizzle, pour, or cascade the warm, velvety cheese sauce generously all over the hot fries.
Sprinkle the crumbled crispy bacon evenly over the cheese sauce.
Dollop the sour cream in several spots over the fries. For a more decorative look, you can thin the sour cream with a tiny bit of milk or water and drizzle it from a spoon or squeeze bottle.
Finally, finish with a vibrant scattering of sliced green onions and jalapeños (if using). Serve immediately and watch them disappear.