Potatoes Lyonnaise

In an electric skillet set to medium-high heat, or in a large fry pan over medium-high heat, melt 2 Tbsp. of the butter. Add the onions, salt and pepper and cook until the onions are tender and lightly caramelized, 10 to 12 minutes. Transfer to a small bowl. Wipe out the skillet with a damp paper towel. Set the skillet to medium-high heat and melt the remaining 2 Tbsp. butter with the olive oil. Add the potatoes and cook, stirring occasionally and being careful not to break up the slices too much, until crisp and golden brown, 8 - 10 minutes. Add the onions and parsley to the pan and stir to combine. Transfer to a warmed serving bowl and serve immediately.