Preheat the oven to 425°F (220°C).
Prepare the potatoes by washing and drying them thoroughly.
Make shallow cuts along the length of each potato, about 1/4 inch apart.
Melt the butter in a small saucepan over low heat, then stir in the minced garlic and rosemary.
Place the potatoes on a baking sheet and brush them generously with the garlic butter mixture, ensuring it seeps into the cuts.
Season the potatoes with salt and pepper to taste.
Bake the potatoes in the oven for about 45–50 minutes, basting with the remaining garlic butter halfway through.
Optional: In the last 10 minutes of baking, sprinkle grated Parmesan cheese on top.
Remove from the oven and let cool slightly before serving.