Preheat oven to 180 degrees. Place the tomatoes on an ovenproof tray. Drizzle with olive oil and a good seasoning of salt and pepper. Roast for 25 minutes.
Lightly toast each piece of bread and then allow to cool. Whisk together the eggs, milk, cheese, mustard, onion and garlic powder and herbs. Add a good grind of cracked black pepper.
Heat a skillet over a medium heat. Add a good glug of oil.
Soak the bread (2 pieces at a time) for a few minutes. Turn it over and make sure it is well coated. As you lift each piece out ensure there is some cheese and herbs on top or spoon it on top when the bread is in the pan. Cook for a couple of minutes on each side until cooked through and golden.
Divide the pieces between plates. Serve with some roasted tomatoes and some sliced avocado.