Preheat the oven to 350°F (175°C).
Peel the potatoes, slice them thinly, and set the slices aside.
Using a hand mixer, blend the cottage cheese until it reaches a smooth, uniform consistency. Set it aside for the sauce.
Warm the olive oil in a frying pan over medium heat.
Add the all-purpose flour to the heated oil and stir thoroughly until the two ingredients combine to form a roux.
Slowly pour in the low-fat milk while stirring continuously. Add the sea salt, garlic powder, and cayenne pepper, then continue mixing until the sauce becomes smooth and begins to thicken slightly.
Lower the heat slightly and stir in the blended cottage cheese. Continue mixing until it is completely incorporated into the sauce.
Lightly coat a casserole dish with olive oil to help prevent the potatoes from sticking.
Arrange half of the thinly sliced potatoes in an even layer across the bottom of the prepared dish.
Spread half of the cottage cheese sauce evenly over the first layer of potatoes.
Arrange the remaining potato slices over the sauce, then distribute the rest of the cottage cheese mixture evenly across the top layer.
Sprinkle the shredded low-fat cheddar or Colby cheese over the casserole, if desired, to create a flavorful, bubbly surface.
Finish the top with the nacho cheddar popcorn seasoning.
Transfer the casserole to the preheated oven and bake for approximately 1 hour, or until the sliced potatoes are tender and the top is golden brown.
Remove the baked scalloped potatoes from the oven and allow the casserole to cool briefly before serving.
This short resting period helps the layers settle and makes the casserole easier to portion. Serve warm.