Heat oven to 350°F. Mix butter, olive oil, garlic and salt in small bowl.
Slice bread into 18 pieces, about 3/4-inch thick, without cutting through bottom crust, so slices stay attached. Spread butter mixture, dividing evenly between slices, about 1 teaspoon. Wrap bread tightly in foil.
Bake in 350°F oven for 15 to 20 minutes or until butter is melted and bread is hot. Unwrap carefully and serve hot.