Preheat the oven to 425 degrees F.
Place the potatoes on a large baking sheet and toss with olive oil, rosemary, sage, the entire smashed garlic cloves, the paprika, and a large pinch of salt. Spread the fries in an even layer. Do not overcrowd the pan, if needed, divide the fries between 2 baking sheets.
Transfer to the oven and bake for 15-20 minutes, then flip and bake for 15 minutes more.
Add the butter and parmesan, toss, and return to the oven for another 5 minutes. You want the potatoes to be tender, yet crispy.
Serve while hot, sprinkled flaky sea salt.
