Place rack in top third of oven; preheat to 500°.
Put the 3 tablespoons of butter into a large (18x12x2-inch) non-stick
roasting pan. Set the pan over medium heat just until the
butter has melted. Remove and add olive oil.
Peel the potatoes and cut in half lengthwise, then cut each
half in half again crosswise. Cut each quarter into 3
wedges. Roll the potato wedges in the roasting pan until
evenly coated with butter and oil. Arrange in the pan so
that they touch as little as possible. Sprinkle with salt
Roast for 15 minutes. Turn wedges with a spatula and
roast for 10 minutes longer. Turn again abd roast 10 minutes
longer. Remove pan from oven. Turn wedges again, making sure
to turn the white sides of each wedge face-up. Add the
broth. Return to the oven for 10 to 15 minutes longer.
Dot the wedges with the 1 tablespoon of butter, and serve hot.