Swiss chard and herb tart with young cheese

Ingredients

½ small red onion, thinly sliced (85g net)
3 celery stalks and leaves, thinly sliced (220g net)
8 large chard (or spinach or kale) leaves, roughly chopped, white stalks discarded (175g net)
2 garlic cloves, thinly sliced
2 tbsp torn mint leaves
2 tbsp chopped parsley
2 tsp chopped sage
2 tbsp olive oil, plus extra for drizzling
75g feta, crumbled
50g pecorino, finely grated
15g pine nuts, lightly toasted
Grated zest of 1 lemon
350g all-butter puff pastry
100g brocciu cheese or ricotta
6 Courgette flowers, cut in half lengthways (optional)
1 egg, lightly beaten
Salt and black pepper

Place a large frying pan on medium-high heat and sauté the onion, celery, chard, garlic, mint, parsley and sage in the olive oil. Cook, stirring continuously, for 15 minutes or until the greens are wilted and the celery has softened completely. Remove from the heat and stir through the feta, pecorino, pine nuts, lemon zest, ¼ teaspoon of salt and a hearty grind of black pepper. Leave aside to cool.
Preheat the oven to 200C.
Roll the pastry to a 3mm thick sheet and cut it into a circle, approximately 30cm in diameter. Place on an oven tray lined with baking paper. Spread the filling out on the pastry leaving a 3 centimetre edge all the way around. Dot the filling with large chunks of white cheese or ricotta top with courgette flowers, if using. Bring the pastry up around the sides of the filling and pinch the edges together firmly to form a secure, decorative lip over the edge of the tart. Alternatively press with the end of a fork. Brush the pastry with egg and refrigerate for 10 minutes.
Bake the tart in the oven for 30 minutes until the pastry is golden and cooked on the base.
Remove from the oven and brush with a little olive oil. Serve warm or at room temperature.