Begin by making the cornmeal crust. Add the flour, cornmeal, sugar, salt and butter to a food processor. Pulse until the butter is the size of peas. Gradually add the ice water, 1 tablespoon at a time, through the feed tube while the machine is on. Add just enough water to bring the dough together.

Wrap the dough in plastic wrap and flatten into a disc. Place in the freezer to chill for 15 minutes.

Add the sliced tomatoes to a large bowl and add the salt. Let the tomatoes sit for 15 minutes while the dough is chilling in the freezer. After 15 minutes, squeeze any excess water from the tomatoes with your hands. Removing excess moisture will prevent the galette from getting soggy. Set aside in a clean bowl and add the basil. Mix to combine.

Preheat the oven to 400 degrees F.

Make the egg wash. Beat the egg and milk in a small bowl. Set aside.

Remove the chilled dough from the freezer and roll out into a round that is 3-millimetres thick on a piece of parchment paper. Use extra cornmeal to dust your surface to prevent the dough from sticking to the parchment paper and rolling pin.

Transfer the parchment paper and dough to a large baking sheet, then pile to tomatoes in the centre of the dough, leaving a 1-inch border around the edges of the dough. Top with extra basil leaves and Parmesan cheese.

Fold the edges of the galette over the tomato filling by 1 inch. You will want to leave a hole in the middle of the galette with the tomatoes showing.

Beat the egg and milk in a small bowl, then use a pastry brush to brush the edges of the crust with the egg wash. Bake in the centre of the oven for 30 to 35 minutes, until golden brown and crisp.

Remove from the oven and let cool for 10 minutes before slicing and serving. Enjoy!