01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish with cooking spray or butter.
02 - Heat olive oil in a skillet over medium heat. Sauté diced potatoes for 5-7 minutes until beginning to soften. Add onion and bell pepper; cook 3 more minutes. Stir in spinach and cook until wilted. Remove from heat and set aside.
03 - In the same skillet, cook diced bacon until crisp. Remove and drain on paper towels.
04 - In a large bowl, whisk together eggs, milk, salt, pepper, and smoked paprika until fully blended.
05 - Layer sautéed vegetables, cooked bacon, bread cubes (if using), and half the shredded cheese in the prepared baking dish.
06 - Pour the egg mixture evenly over the layered ingredients. Sprinkle remaining cheese on top.
07 - Bake for 35-40 minutes until eggs are completely set and the top is golden brown.
08 - Let casserole rest for 5 minutes before serving. Garnish with fresh chives or parsley.