- Peel the potatoes and place in a pot, fill to the top with water. Salt to taste. Bring to a boil and cook until the potatoes are cooked through and tender in the center, about 15 minutes. Drain the potatoes. Meanwhile, in a large skillet, melt the butter and add the chopped onion. Season with salt and ground black pepper to taste. Cook for about 5 minutes, just until the onion are translucent and tender. Add the frozen peas, cooking in the skillet for 1-2 minutes, just until the peas heat through. Mix gently to combine. Serve immediately.