1/4 cup finely chopped parsley Divide butter and oil between two 9- inch diameter nonstick skillets and cook over medium heat until butter melts. Divide onion between skillets and saute until tender, about S minutes. Increase heat to medium-high. Divide potatoes, garlic, rosemary and salt between skillets and cook until potatoes are light golden, turning often, about 10 minutes. Using metal spatula, press and flatten potatoes into uniform thickness. Cover; reduce heat to medium and cook until potatoes brown on bottom, about 15 minutes. Place 1 large plate over 1 skillet. Using oven mitts, hold plate and skillet together and turn skillet over, releasing potato galette onto plate. Slide galette back into skillet. Repeat with remaining potato galette. Cook until potatoes brown on bottom, pressing with spatula, about 15 minutes. Slide galettes out onto plates. Sprinkle with parsley.