Creating your Savory Spinach and Feta Breakfast Galette is simple when following these clear steps:

1. Preheat Oven: Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.
2. Make the Dough: In a large bowl, mix the flour, salt, and baking powder. Add the cubed butter and mix until the mixture resembles coarse crumbs.
3. Add Ice Water: Gradually stir in the ice water, one tablespoon at a time, until the dough begins to come together. Form a ball, wrap it in plastic wrap, and refrigerate for 30 minutes.
4. Prepare Filling: In a skillet over medium heat, sauté the chopped spinach until wilted (about 3-4 minutes). Remove from heat and let it cool slightly.
5. Combine Ingredients: In a mixing bowl, combine the wilted spinach, crumbled feta, egg, dried oregano, and black pepper. Mix until well incorporated.
6. Roll Out Dough: On a lightly floured surface, roll out the chilled dough into a 12-inch circle, about ¼ inch thick. Transfer it to the prepared baking sheet.
7. Fill the Galette: Spoon the spinach and feta mixture into the center of the dough, leaving a 2-inch border.
8. Fold the Edges: Gently fold the edges of the dough over the filling, creating pleats and leaving the center open.
9. Brush with Egg Wash: In a small bowl, beat the egg yolk and brush it over the folded edges of the galette to achieve a golden color while baking.
10. Bake: Bake in the preheated oven for 30-35 minutes, or until the crust is golden brown and flaky.
11. Cool and Serve: Remove the galette from the oven and let it cool for about 10-15 minutes before slicing.

Your incredible Savory Spinach and Feta Breakfast Galette is now ready to be enjoyed!