Spread shrimp and spinach mixture evenly in skillet. Pour egg mixture into skillet. Use a spatula to lift shrimp and spinach mixture, allowing egg mixture to flow underneath. Sprinkle goat cheese on top. Once the frittata is set on the bottom, transfer to oven and bake 13 to 15 minutes, until puffy and golden brown. Remove from oven and let cool a few minutes before cutting into wedges.