Preheat the oven to 350ºF. Heat the olive oil in a deep oven-safe skillet or Dutch oven over medium heat and saute the onion, bell pepper, and jalapeño until tender, about 10 minutes.
Add in the garlic, cumin, chili powder, and cayenne pepper, if using, and saute for one more minute. Add in the chopped tomatoes, salt, and cauliflower rice and stir well. Once the tomatoes start simmering, lower the heat and cover the pan to let the vegetables cook until tender, about 8 to 10 minutes.
Once tender, turn off the heat, remove the lid and give the vegetables a stir. Adjust any seasoning to taste then add in the beaten eggs. Stir well to make sure the eggs are well incorporated throughout the vegetables. Top with a sprinkling of cheese, then place the pan in the oven to bake for 30 minutes at 350ºF.
The casserole is done when the eggs are cooked through and the cheese is bubbly and staring to turn golden. Let the casserole rest for 10 minutes before serving.
Leftovers can be stored in an airtight container in the fridge for up to a week.