Preparation

• Position a rack in the center of the oven, and heat the oven to 400°f.
• Heat the oil in a large nonstick skillet over medium-high heat. Add the leeks and cook, stirring occasionally, until soft and lightly browned, about 5 minutes. Add the garlic and cook until aromatic, about 1 minute. Stir in the artichokes, sun-dried tomatoes, parsley, thyme, 1/4 tsp. salt, and 1/4 tsp. pepper. Remove from the heat.
• Lightly flour a work surface. Roll the puff pastry on a sheet of lightly floured parchment and cut into a 12-inch square. Slide the parchment onto a large rimmed baking sheet.
• Cut the cheese crosswise into thin slices.
• Leaving a 1/2-inch border, scatter three-fourths of the cheese over the pastry. Spoon the leek mixture on top of the cheese. Brush the pastry edges lightly with water and fold the edges over and onto the filling, pressing down lightly to seal.
• Bake until golden brown, about 30 minutes. Break the remaining cheese into small pieces and dot the top of the galette with the cheese. Let stand until cheese melts, about 10 minutes. Slice and serve.