1Spray 4- to 5-quart slow cooker with cooking spray. In slow cooker, beat eggs, milk and Bisquick mix with whisk until well mixed. Add spinach, 1 1/2 cups feta cheese, the bell peppers, basil, garlic and sausage; stir well.
2Cover; cook on High heat setting 3 to 4 hours or on Low heat setting 5 to 6 hours. Quiche is done when center is set and edges are deep golden brown.
3Cut into pieces to serve. Garnish each serving with a sprinkle of feta cheese.