Start by chopping the broccoli and the caulifower into florets and remove their stems.
Transfer the broccoli and the cauliflower florets to a saucepan, season them with salt, add enough water to cover these vegetables and add the milk. Bring to a boil on medium heat and cook for 10 to 15 minutes.
Meanwhile, chop the onion into dices, transfer them to a skillet greased with 1 drizzle of olive oil and sauté them until slightly golden brown.
Cut the yellow peppers into strips and set aside.
Drain the water from the broccoli and cauliflower and transfer these florets to a baking dish, also add the sautéed onion and all the yellow pepper strips, set aside.
Chop the tomato into medium dices, transfer them to the baking dish and set the baking dish aside.
In a bowl, place the eggs, season them with 1 teaspoon of salt, mix well until combined. Add the oil or olive oil and the wheat flour, mix very well again. Add the milk and some chives and parsley to taste, mix well and pour all this mixture into the baking dish, over the vegetables.
Finally, top it all with some grated mozzarella cheese.
Bake in a preheated oven at 200°C (392°F) for 30 to 40 minutes.
Note.: Baking time may vary depending on the power of your oven.
Serve.