Preheat the oven to 375 - spray a 9x9" pan with non-stick cooking oil.
Start by dicing the red pepper and onion. Dice them pretty small, about a ¼ inch dice.
Heat a sauté over medium heat on the stove. Add 1 tablespoon olive oil & the pepper & onion. Saute for about 5-6 minutes until the veggies just begin to get soft. Remove from heat and set aside to cool in a large bowl.
While the vegetables are cooking, peel (if desired) and dice the potatoes. (Remember these are leftover baked potatoes and so they are already cooked). Dice them into about ½ dice. Slice the green onions. Add the potatoes & onions to the bowl with the sautéed vegetables.
Shred the cheese & place ¾ cup of the cheddar and parmesan cheese in the bowl with the vegetables. (Save ¼ cup cheese to top the casserole.) Carefully mix the ingredients in the bowl together and pour into the greased casserole dish.
In a separate bowl crack the eggs and add the sour cream and tabasco sauce - plus ½ teaspoon (each) salt and pepper. Whisk together well and slowly pour over the casserole, be sure to distribute well thru-out the casserole. Sprinkle with remaining cheese and place in the preheated oven.
Bake for 35 minutes or until the eggs are set & the top of the casserole is lightly browned.