In a food processor, pulse the flour, butter, Parmesan, rosemary, and salt until sandy. Add egg yolk and 1–2 tbsp cold water, pulse until chunky. Shape into a disc, wrap, and chill for 30 minutes or up to 24 hours.
Preheat to 190°C (375°F).
Mix the labneh with chopped chives. Slice the potato very thin. Toss potatoes with olive oil and salt.
Roll the dough on floured parchment to ½ cm thick. Spread the labneh mixture in the center, leaving a 4 cm border. Arrange potatoes over the labneh. Sprinkle with Parmesan and feta.
Fold the edges over the filling to form a crust. Brush with beaten egg.
Bake for 35 minutes or until golden and crispy.
Course Main Course
Cuisine French
Keyword easy savory tart, galette with roasted vegetables, rustic vegetable tart, savory galette, savory galette recipe, vegetable galette, vegetarian galette recipe