Prepare the Vegetables: In a large frying pan, heat a splash of olive oil over medium heat.

Add the chopped red onion and fry for 5-7 minutes until it starts to soften.

Add Carrots: Add the sliced carrots to the pan and continue to fry for 10 minutes, stirring occasionally.

Add Peppers: Add the chopped peppers, cover with a lid, and let them cook for 10 minutes.

Add Zucchini: Add the sliced zucchini to the pan.

Season with 1/2 tablespoon of salt and black pepper to taste.

Cover with a lid and boil for 12 minutes.

Final Cooking of Vegetables: Mix all the vegetables well and cook uncovered for an additional 5-7 minutes to allow excess moisture to evaporate.

Prepare Egg Mixture: In a separate bowl, beat the 3 eggs.

Add a pinch of salt and black pepper to taste.

Pour in 300 ml of milk and whisk together.

Gradually add 4 tablespoons of flour, whisking until smooth.

Stir in the shredded cheese until well combined.

Combine and Bake: Preheat your oven to 180°C (350°F).

Grease a baking dish with a little olive oil.

Spread the cooked vegetables evenly in the baking dish.

Pour the egg and cheese mixture over the vegetables, ensuring it is evenly distributed.

Bake: Place the baking dish in the preheated oven.

Bake for 35 minutes or until the casserole is set and the top is golden brown.

Serve: Once baked, remove the casserole from the oven and let it cool slightly before serving.

Enjoy your meal!