Prepare the Vegetable Mixture: Grate the zucchini and potatoes, and sprinkle with 1 tsp of salt. Let them sit for 10 minutes, then squeeze out excess moisture.

In a large pan, heat olive oil and sauté the onion, garlic, carrot, and sweet red pepper for about 5 minutes. Season with 1 tsp salt, black pepper, and Provencal herbs.

Make the Egg Mixture: In a bowl, whisk together eggs, milk, wheat flour, baking powder, 1 tsp salt, and black pepper.

Add the spring onions, dill, and the squeezed zucchini-potato mixture. Mix everything well.

Assemble the Casserole: Grease a baking dish with olive oil and pour the egg and vegetable mixture into it.

Top with the sautéed onion and pepper mixture, then sprinkle with shredded mozzarella cheese.

Bake in a preheated oven at 180°C/360°F for 30 minutes, or until golden and set.

Make the Garlic-Cucumber Sauce: In a small bowl, combine mayonnaise, sour cream, minced garlic, and diced cucumber.

Mix well and refrigerate until ready to serve.

Serve: Let the casserole cool slightly before slicing.

Serve warm with a generous dollop of garlic-cucumber sauce on the side.