Frittata con Patate

3 medium Yukon Gold potatoes, peeled5 tablespoons extra virgin olive oilSalt and pepper to taste1 medium Spanish onion, finely chopped, about 11/2 cups10 large eggs#188; cup whole or 2 percent milk4 tablespoons fresh basil, finely chopped1#189; cups Gruyere cheese, shreddedSet broiler on high.Place potatoes on microwave-safe dish and cook on high for 2 minutes; remove and cool slightly; quarter lengthwise and slice about#8539;inch thick. Place in bowl and add 1 tablespoon of the oil, salt and pepper to taste; mix to coat well.Pour 3 tablespoons of oil in a nonstick, ovenproof skillet over medium heat. Saute potatoes and onions until potatoes are tender and onions are translucent; do not caramelize, about 10-15 minutes.Crack eggs into a bowl, season with salt and pepper; add milk and basil; whisk until frothy. Add potatoes and onions to the eggs, stir well. Return skillet to stovetop over medium heat; add remaining 1 tablespoon oil and pour egg and potato mixture in pan. Stir and cook until mixture begins to firm up.Sprinkle frittata with cheese, place under broiler and cook until frittata feels firm, about 4 minutes. Return to stovetop for 2 to 3 minutes; run a silicone spatula around the edge to loosen frittata; return to broiler until cheese becomes golden brown. Invert frittata onto serving dish; place another serving dish on top and invert again to that cheese side is up. Serve hot or cold.Serves five.