Grease 9x13" pan with cooking spray. Set aside.
Cook bacon in large skillet until done to your liking. Remove from skillet and let cool on plate lined with paper towel.
Once cool, chop into pieces.
In same skillet leave 1 tbsp of bacon grease and cook diced onion over medium-high heat for 5 minutes.
Add broccoli and cook another 3-4 minutes, until broccoli brightens in color and is slightly cooked. Set aside.
In large bowl, whisk together eggs, milk, yogurt, and dijon mustard.
Add green onions, cheese, bacon, salt and pepper.
Place cubed bread pieces in prepared pan.
Pour egg mixture over bread.
Cover with plastic wrap and refrigerate 8 hours, or overnight.
When ready to bake, remove from refrigerator and let sit 30 minutes.
Preheat oven to 350 degrees.
Bake in preheated oven 45-55 minutes, until it is baked through.
Let sit for 5 minutes, then serve.