Remove the sides of the bread and arrange them on a flat surface in a rectangular shape in 4 rows of 2 slices each. The slices should overlap each other slightly without any gaps in between. Make sure that the overall size is bigger than the tart pan that you will use for baking.

Brush the edges of the breads with some water, press them gently with your hands, and then flatten them with a rolling pin. This will seal all the edges and it will become one large piece of bread.

Now, carefully transfer the large piece of bread to a greased rectangular tart pan. I used a 5"x14" removable bottom tart pan.

Press the bread along all the sides and edges so that it takes the shape of the pan. Remove any extra pieces with the help of a knife or scissors. Check out the video in this recipe for making the bread tart shell.

Now, brush the tart shell with melted butter (or olive oil) and lightly bake in a pre-heated oven at 350°F/175°C for 8-10 minutes. Make sure that you only half bake the tart and take it out of the oven before it changes color as we will be baking them again with the sauce/veggie filling later.

Leave the half-baked tart in the the pan as we will be baking it again later.

In a lined baking tray, mix all the vegetables (except garlic), oil, italian seasoning, salt, and pepper together. Spread them on the tray in an even layer.

Slice the top part of the garlic, sprinkle some oil, and wrap in a foil. Keep the foil in the baking tray along with the vegetables. We will use the roasted garlic in the bechamel sauce later.

Bake the vegetable in a pre-heated oven at 350°F/175°C for 10-15 minutes. The vegetables should be crisp and not over-cooked as we will be adding them to the bechamel sauce.

Keep 2 tbsp veggies aside for garnishing the tart.

Heat oil and butter in a large saucepan and allow them to melt.

Add all purpose and corn flour and whisk the mixture so that it becomes frothy with a slight change in color.

Reduce the heat to low and gradually whisk in milk, making sure to eliminate lumps from the mixture.

Add in your red chili flakes, salt , sugar, and peeled roasted garlic.

Now, increase the heat and and keep stirring the mixture until it starts thickening up. It should be of pouring consistency like a pancake batter.

Then, switch off the heat, add in your roasted vegetables, torn basil leaves, feta cubes, roasted pistachios, and mozzarella cheese. Mix them together and adjust the seasonings according to your taste. Your sauce/veggie filling is ready.

Take a half-baked tart shell and fill it with the bechamel sauce/vegetable filling. Garnish it with roasted vegetables.

Bake the tart in a pre-heated oven at 350°F/175°C for 10-15 minutes or until it is crispy and the edges are golden.

Then, remove the pan from the oven and leave it for 5 minutes on the counter.

Now, unmold the tart. An easy way to do this is to place the cooled tart pan on top of a couple of glasses. Then hold the pan ring and gently pull it down.

Your Vegetable Au Gratin Bread Tart is ready! Enjoy immediately!