Filling
Into a blender, add the milk, the oil, the eggs and the salt, blend until combined. Transfer to a bowl, add the wheat flour and the baking powder and mix very well.
Grease a round baking pan with removable bottom with butter and flour, and pour in half of the batter.
Spread well and bake in a preheated oven at 180°C (356°F) for 15 to 20 minutes.
Once it has baked through, remove the pie from the oven and spread the tomato sauce, add the ham, the canned vegetables, the boiled and chopped eggs, the sliced onions, the cheese (set 100g aside), top with the tomato slices and some oregano to taste.
Pour the rest of the batter, spread well and sprinkle the rest of the mozzarella cheese and some more oregano to taste on top.
Bake in a preheated oven at 180°C (356°F) for 35 to 55 minutes or until browned, serve.