Heat the olive oil and sauté the tomato, bell pepper and onions for 1 - 2 minutes. Add the crushed garlic, red chilli flakes, spinach, salt and pepper and continue to sauté until the spinach is wilted.
Meanwhile in a separate bowl, break the eggs and whisk lightly, and set aside. Preheat your oven to 200 degrees (180 degrees if fan-assisted).
Distribute your muffin holders into a muffin pan (include this step to decrease dramatically your washing up time!).
Scoop the sautéed vegetables into each muffin holder, and then top by pouring the egg mixture into the compartment. Bake for 15 - 18 minutes