Wash potato slices then dry them completely and set to the side.

In a large bowl, add salt, pepper, paprika, onion powder, and garlic powder. Whisk together until combined; taste and adjust seasoning if needed, then set aside.

Preheat oven to 400°F. Grease a large casserole dish with a cover.

In a medium pot over medium heat, melt butter. Whisk in flour until completely combined.

Whisk in half-and-half and ½ cup each of monterey jack cheese and colby cheddar cheese until combined, then remove from heat and set aside.

Add dried potato slices to the seasoning bowl and toss to coat evenly.

For horizontal layers, add half of the potatoes in one layer to the pan, pour half of the cheese sauce over them, and spread out to cover. Repeat with the remaining potatoes and cheese sauce, ensuring all potatoes are covered.

For vertical scalloped potatoes, add all potatoes to the pan, pour cheese sauce on top, and sprinkle with cheese. Ensure potatoes are completely covered in sauce.

Bake covered in the oven for 30 minutes. Remove the cover and bake for an additional 30-50 minutes until cheese is melted, bubbly, and potatoes are tender.

Remove from oven and allow to cool for 10-15 minutes before serving.