Sweet potato and red onion frittata

Name: Sweet potato and red onion frittata
Cuisine: European, American, Mediterranean
Ingredients: 3 medium sweet potatoes, peeled and chopped; 1 large red onion, chopped; 4 tablespoons extra virgin olive oil; Salt; Freshly ground black pepper; 3 cups baby kale, chopped; 12 eggs, beaten; 6 ounces goat cheese, crumbled