Heat the oven to 450 degrees F. Slice the potatoes on a sharp angle into 3/8-inch slabs. Put them in a colander and rinse (this way you rinse off dirt and lose a little starch for crisper planks). Shake off the excess water and spread them onto a heavy rimmed baking sheet (about 11x18-inches) lined with two layers of paper towels. Cover with a few more paper towels and let dry.
Done just right, crispy roasted potatoes are an almost-perfect side. We know potatoes pair perfectly with rosemary, but this variation takes it one step further by coating the potatoes in cornmeal and parmesan and roasting in a bed of rosemary and garlic. Don't mind if we do!