Preheat the oven to 425F or 400F convection. Line a baking sheet with parchment paper.
Add potatoes to the baking sheet (see pro tip!). Drizzle the olive oil over top and sprinkle all over with salt and pepper. Use your hands to toss to coat. Add the parm and toss to coat again.
Arrange the potatoes in a single layer. Try to spread the parmesan around the pan and place the flat side of the potatoes on top of the cheese. This will give you a crispy cheesy potato bottom.
Bake for 25-30 minutes or until the potatoes are cooked through and browned in spots and the cheese is golden. Let cool for 10 minutes to let the cheese crisp up, then transfer to a platter, with the cheesy cut-side up. Carefully tear/break the potatoes up if they are stuck together from the cheese.
To make the gremolata (if using), add parsley, garlic, and lemon zest to a small bowl and use your hands to mix/massage the garlic and zest into the parsley to thoroughly combine.
Serve the potatoes warm and top with the gremolata (if using).