Method

• 1.
  For the dough, place the flour, 2 tsp salt, butter and Gruyere in a bowl. Using your fingers, rub the butter into the flour until almost combined. Add a splash of cold water to bring the dough together. Shape into a disc and enclose in plastic wrap. Refrigerate for 1 hour to rest.
• 2.
  Meanwhile, heat a large frypan over low heat. Add onion and butter and season. Cover pan and cook gently for 20-30 minutes, stirring occasionally, or until onions are soft and jammy. Transfer to a bowl and set aside to cool. Return pan to heat and add silverbeet, oil and garlic.
• 3.
  Cook for 6-8 minutes, stirring occasionally, until just wilted. Remove from heat. Toss through nutmeg and lemon juice.
• 4.
  Preheat oven to 200°C/180°C fan-forced. Roll out the dough between two sheets of baking paper to form a 35cm-diameter circle, about 3mm thick. Remove the top layer of baking paper. Spread mustard and creme fraiche over the pastry, leaving a 3cm border around the edge. Top with the jammy onion, then scatter with Gruyere. Top with silverbeet. Using the baking paper, slide galette onto a baking tray.
• 5.
  Gently fold over the edges of the pastry to enclose the topping slightly. Brush the edge with egg wash. Bake for 40-50 minutes, until pastry is golden. When there are 10 minutes of cooking time remaining, remove galette from the oven.
• 6.
  Gently make 4 indents into the silverbeet and crack eggs into each hole. (Don’t worry if white spills out a bit.) Bake for a further 9-10 minutes until the eggs are cooked to your liking. Cool for 10 minutes. Season with salt and pepper.
• 7.
  Serve galette warm, scattered with parsley leaves and extra Gruyere.