Preheat grill to 350°.

Scrub potatoes and dry well.

Cut potatoes into wedges and place in a large bowl.

In a small saucepan melt butter with olive oil and minced garlic. Cook over low heat for about 2- 3 minutes until garlic becomes fragrant.

Remove from heat and mix in rosemary, salt and pepper.

Drizzle over potatoes and mix thoroughly.

Create a foil packet with heavy duty foil or 2 layers of standard foil.

Pour potatoes and all of the garlic butter mixture into packet.

Seal packet and place over indirect heat on the grill.

Cook with the grill closed for 45 minutes to 1 hour.

Remove from grill and carefully open the packet, watching for steam.

Toss potatoes with butter mixture in the bottom of the packet and serve immediately.