Heat oven to 375°F.
Cook mushrooms and onions in large nonstick skillet sprayed with cooking spray on medium-high heat for 5 minutes or until crisp-tender. Remove from heat; stir in spinach.
Beat eggs, milk and dressing in medium bowl with whisk until well blended. Add spinach mixture and cheese; pour into crust. Top with bacon bits.
Bake 50 minutes or until center is set and top is golden brown.
Serving Suggestion: Serve this entree with a mixed green salad tossed with a light salad dressing, a whole grain roll and fresh fruit for dessert.
To Thaw Frozen Spinach: Place spinach block in colander in sink. Run hot water over spinach until thawed; press out any excess liquid.
Creative Leftovers: A slice of quiche, served warm or cold with a tossed salad is a perfect lunch to take to work the next day.