Creating the Savory Leek Galette can be simple if you follow these steps:

1. Make the Dough: In a large bowl, combine the flour, salt, and sugar. Add chilled butter and mix until it resembles coarse crumbs.
2. Add Ice Water: Gradually stir in ice water, one tablespoon at a time, until the dough begins to come together. Shape into a ball, wrap in plastic wrap, and refrigerate for at least 30 minutes.
3. Sauté the Leeks: In a skillet, heat olive oil over medium heat. Add sliced leeks, salt, and black pepper. Cook for about 10 minutes until soft and lightly caramelized. Stir in thyme and set aside to cool.
4. Preheat Oven: Preheat your oven to 400°F (200°C) while dough is chilling.
5. Roll Out the Dough: On a lightly floured surface, roll out the dough into a large circle (about 12 inches in diameter). Transfer to a parchment-lined baking sheet.
6. Add Filling: Sprinkle shredded cheese in the center of the rolled dough, leaving a border of about 2 inches. Top with sautéed leeks.
7. Fold Edges: Gently fold the edges of the dough over the filling, pleating it as you go to form a border.
8. Egg Wash: Brush the folded edges of the dough with the beaten egg for a golden crust.
9. Bake: Bake in the preheated oven for 35-45 minutes, or until the crust is golden brown and the filling is bubbly.
10. Cool: Remove the galette from the oven and let it cool for about 15 minutes.
11. Garnish and Serve: If desired, garnish with fresh herbs before slicing and serving.

By following these steps, you’ll create an incredible Savory Leek Galette that will surely impress your guests!