Oven-baked potato fingers with cheese

Ingredients:

• 6 cups frozen Tater Tots, from an 800g bag
• 3 tbsp vegetable oil + extra to grease the pan
• 1 small onion, finely chopped
• 1 red bell pepper, finely chopped
• 1 green bell pepper, finely chopped
• 220 g thin slices of corned beef, cut into 1 cm pieces.
• 8 large eggs
• 1.5 cups whole milk
• 3/4 tsp mustard powder
• 4 drops hot sauce, or to taste
• 1.5 cups grated cheddar

Preparation:

1. Preheat oven to 230°C and grease a 22 x 32 cm baking dish with vegetable oil.
   
   Place a layer of potato balls (about 4 cups) in the bottom of the pan. Drizzle with 1 tablespoon of vegetable oil. Bake until crisp, about 20 minutes. Let cool for 15 minutes.
2. Meanwhile, heat the remaining 2 tablespoons of vegetable oil in a large skillet over medium-high heat. Add the onion and red and green bell peppers. Season with 1/2 teaspoon of salt and a small amount of freshly ground black pepper. Cook, stirring occasionally, until the vegetables are softened and beginning to brown, about 6 minutes. Add the corned beef and cook for another 2 minutes. Let cool.
3. In a large bowl, whisk together the eggs, milk, mustard, hot sauce, 1/2 teaspoon salt, and 1/4 teaspoon freshly ground black pepper.
4. Sprinkle the potato balls with 1/2 cup of cheddar. Top with the vegetable and corned beef mixture. Pour the egg mixture over them and sprinkle with the remaining cheddar. At this point, the casserole can be refrigerated overnight. Remove from the refrigerator 30 minutes before baking.
5. Preheat oven to 350°F (175°C) and top the casserole with the remaining potato balls (about 2 cups). Bake until the egg mixture is set and the top is golden brown, 50-60 minutes. Let cool for 15 minutes and serve warm or at room temperature.