1. Preheat oven to 375 degrees. Heat oil and butter in a 10-inch ovenproof nonstick skillet over medium heat. Add potatoes; season with salt and pepper. Cook, stirring occasionally, until potatoes are tender and golden brown, 12 to 15 minutes. Stir in herbs.

2. Meanwhile, whisk the eggs in a medium bowl; season with salt and pepper. Stir in the cheese; pour mixture over potatoes. Stir until eggs begin to set slightly, about 30 seconds. Without stirring, continue cooking until eggs are set on the sides and bottom, about 2 minutes. Transfer skillet to oven; bake until just set, 12 to 15 minutes.

3. Slide frittata onto a serving platter, or let cool and slide into a 10-inch pie plate (and cover with a second pie plate) for easy transport. Serve garnished with chopped herbs if desired.