Bring a pot of water to a boil. Prepare a large bowl of ice water. 

Blanche basil leaves for ten seconds. Place in bowl of ice water to prevent basil from cooking further. Remove and pat dry with paper towel, making sure basil is completely dry. 

Blend basil leaves and evoo in a high powered blender until smooth. Set aside. 

Preheat oven to 400°F. 

Peel potatoes and slice an ⅛-inch thick using a mandolin, a sharp knife, or slicer blade of food processor. 

Mix basil oil, salt, and pepper together in a bag or bowl.

Add potatoes to the bowl and coat evenly with oil. 

Brush two tablespoons of basil oil in a 9-inch baking dish.

Place the potatoes vertically in the prepared dish. 

Wedge garlic slices in between potato slices. 

Cover dish and bake at 400°F for 45 minutes. Uncover and bake 30 minutes more, or even longer, so top gets golden brown. Keep in the oven at 200°F until ready to serve.