Step 1: Prepare the Potatoes - Start by washing the russet potatoes thoroughly under running water to remove any dirt. Once clean, pat them dry with a kitchen towel.
Step 2: Slice the Potatoes - Using a sharp knife and a cutting board, slice the potatoes into even rounds, about 1/4 inch thick.
Step 3: Season the Potatoes - In a mixing bowl, combine the sliced potatoes with olive oil, salt, pepper, garlic powder, onion powder, and dried rosemary if using. Toss everything together until well coated.
Step 4: Arrange on a Baking Sheet - Spread the seasoned potato slices in a single layer on the baking sheet.
Step 5: Bake - Place the baking sheet in the preheated oven and bake for 25-30 minutes, flipping halfway through.
Step 6: Garnish and Serve - Once out of the oven, let the potatoes cool briefly. Garnish with freshly chopped parsley and serve warm.