Preheat oven to 425 degrees F. Line 2 baking sheets with tin foil and generously rub olive oil( I have olive oil spray and love it) all over each sheet. Arrange potato slices in one layer on the oiled baking sheets. Use more olive oil to brush on the potato tops. Season generously with salt and ground black pepper.
Roast for 30 minutes, until golden brown underneath. The potato slices can hold for a few hours now and be reheated at 400 degrees F with a sprinkling of cheddar cheese on each slice for 5 minutes, until the cheese is melted and bubbly.
Top each crisp with a small dollop of sour cream, bacon crumbles and chives or green onion.