Heat oil in large nonstick skillet over medium-high heat. Add onion and garlic; cook, stirring often, until tender, 3 to 4 minutes. Add mushrooms; cook, stirring occasionally, until excess moisture has evaporated and starts to brown, 4 to 5 minutes. Add the salad blend and cook, stirring until wilted and almost dry, 3 to 4 minutes. Remove from heat; cool slightly.
Mix together cooled vegetables and swiss cheese. Sprinkle 1/2 parmesan cheese on bottom of pie shell. Top with vegetable mixture.
Stir together eggs, half and half, salt and spices; pour into pie shell. Sprinkle with remaining parmesan cheese. Bake 30 to 35 minutes or until knife inserted near center comes out clean.