Step 1

To make the crust in a food processor: Combine the flour, cornmeal, salt, and pepper in a food processor and pulse to combine. Cut the butter into 6 pieces and add to the food processor and pulse till the butter is in small, pea-sized pieces OR add it to the mixing. Then add the egg and 1 tablespoon of the ice water and pulse again. Add 1 tablespoon of water at a time and continue to pulse till the dough comes together in a ball - it might take up to 4 tablespoons of water. Remove the dough, knead it a few times, and pat it into a disk. Cover with plastic wrap and chill it for 30 minutes.

Step 2

To make the crust in a bowl: Combine the flour, cornmeal, salt, and pepper in a mixing bowl and stir to combine. Cut the butter into 6 pieces and add to the bowl and cut with a pastry cutter until the butter is pea-sized. Then add the egg and 1 tablespoon of the ice water and continue to combine with the pastry cutter. Add 1 tablespoon of water at a time and continue to combine till the dough comes together - it might take up to 4 tablespoons of water. Remove the dough, knead it a few times, and pat it into a disk. Cover with plastic wrap and chill it for 30 minutes.

Step 3

Preheat the oven to 375 degrees F (190 C). Remove dough from the fridge and roll out into a circle with 1/4 inch thickness on a floured surface. Place on a baking sheet.

Step 4

To make the filling: Add the olive oil to a large frying pan and warm it over medium heat. Add the garlic and sauté for 30 seconds, then add the mushrooms and sauté for 3 minutes. Add the spinach one handful at a time until it is all wilted. Add a sprinkle of salt and give the filling a final stir and remove from the heat.

Step 5

Place the mozzarella slices around the dough, leaving a 2-inch lip on the dough (this is what you will fold over to create the crust). Then add half the mushroom spinach filling. Sprinkle half the pecorino on top, then add the rest of the filling and sprinkle the rest of the pecorino on top. Add a few bits of rosemary. Fold the edge of the dough over the filling. Beat the second egg and brush it onto the crust.

Step 6

Bake for 45 minutes or until golden brown. Allow the galette to cool for a few minutes before serving. Add rosemary or thyme to garnish, if desired.