• 1 roll of all-butter puff pastry
• 1kg onions
• A knob of butter
• A drizzle of olive oil
• 1 egg, beaten
• 3 tins of anchovies
• 2–3 tomatoes, sliced
• A handful of capers
• A few sprigs of thyme
• A pinch of sea salt

Peel the onions, halve them, then slice them into thin half-moons.

Heat the butter and a drizzle of olive oil in a heavy-based frying pan. Add the onions with a pinch of sea salt and cook gently over a low heat for about 30 minutes, stirring occasionally, until they are soft, sweet and lightly caramelised. If they begin to catch, add a small splash of water. Leave the onions to cool completely.

Preheat the oven to 200°C.

Line a baking tray with baking parchment and place the sheet of puff pastry on top.

Using a sharp knife, lightly score a border about 1.5cm from the edge without cutting all the way through. This will create a beautifully raised edge as the pastry bakes. Brush the border with the beaten egg.

Spread the cooled onions evenly over the pastry, keeping within the scored border. Arrange the anchovy fillets diagonally across the onions to create a diamond pattern, leaving enough space to place a slice of tomato in the centre of each diamond. Scatter over the capers and thyme leaves.

Finish with a drizzle of olive oil and bake for about 30 minutes, until the pastry is crisp and golden.