In a large skillet set of medium-high heat, place bacon and cook, turning frequently, until nicely crisp.
Preheat oven to 350°, if baking immediately.
Meanwhile, spray a 9 x 13" baking dish with cooking spray. Then, cover bottom with 1/2 of hash browns.
Once bacon is cooked, crumble. Then add bacon and cheddar cheese to hash brown misture, spreading evenly.
Pour all but 1 Tbsp of grease out of bacon skillet. Place pepper and mushrooms and pan and saute until soft. When soft, spread pepper and mushrooms over all in baking dish. Top with remaining 1/2 of hash browns.
Beat eggs, milk, ricotta and salt + pepper together and pour over potato mixture.
At this point, either bake, uncovered at 350° for roughly 45 minutes or until nicely browned.
This dish can also be made ahead, covered and refrigerated until the next morning. Then, just slide into preheated oven and relax!