Dice the onion into 1/4-inch pieces and both bell peppers into 1/2-inch pieces, keeping them separate for even cooking. Melt the butter in a large skillet over medium heat and add the diced onion first, cooking for about 2 minutes until it begins to soften. Then add both the green and red bell peppers, stirring occasionally, and cook for another 5-7 minutes until the peppers are tender but still have a slight bite to them. While the vegetables cook, preheat your oven to 350°F and grease a 9x13-inch baking dish. I like to use a little butter on my hands to grease the dish evenly—it prevents sticking better than cooking spray.

Crack all 12 eggs into a large mixing bowl and whisk them together until well combined. Season generously with salt and freshly ground black pepper to taste. Add the sautéed vegetables from Step 1 to the eggs along with 1 cup of the shredded cheddar cheese, and whisk until everything is evenly distributed. I find that sharp cheddar really elevates the flavor of this casserole compared to mild varieties, so don't skimp on quality here.

Pour the egg mixture from Step 2 into the prepared 9x13-inch baking dish, distributing it evenly. Scatter the frozen tater tots directly over the egg mixture—no need to thaw them, as they'll cook perfectly from frozen and maintain their crispy edges. Sprinkle the remaining 1/2 cup of cheddar cheese over the top, ensuring it's distributed fairly evenly. Bake at 350°F for 30-35 minutes, until the eggs are set in the center and a knife inserted into the middle comes out clean. The tater tots will turn golden brown and crispy on top while the casserole cooks.

Remove the casserole from the oven and let it rest for 2-3 minutes before serving—this allows the eggs to set fully and makes serving cleaner. Garnish generously with fresh chopped cilantro and serve warm with salsa and sour cream on the side so guests can customize their portions to their preferred heat level and richness.