Caramelized Onion Quiche Recipe

<ul class="ingredients-main-list"><li class="ingredients-single-item">For the pastry:</li><li class="ingredients-single-item">200g plain flour</li><li class="ingredients-single-item">100g cold unsalted butter, cubed</li><li class="ingredients-single-item">1/4 tsp salt</li><li class="ingredients-single-item">3-4 tbsp ice-cold water</li><li class="ingredients-single-item">For the filling:</li><li class="ingredients-single-item">4 large onions (about 800g), thinly sliced</li><li class="ingredients-single-item">30g unsalted butter</li><li class="ingredients-single-item">2 tbsp olive oil</li><li class="ingredients-single-item">1 tsp granulated sugar</li><li class="ingredients-single-item">1 tbsp balsamic vinegar</li><li class="ingredients-single-item">2 tsp fresh thyme leaves (or 1 tsp dried)</li><li class="ingredients-single-item">4 large eggs</li><li class="ingredients-single-item">200ml double cream</li><li class="ingredients-single-item">100ml whole milk</li><li class="ingredients-single-item">100g Gruyère cheese, grated (or mature cheddar)</li><li class="ingredients-single-item">1/4 tsp freshly grated nutmeg</li><li class="ingredients-single-item">Salt and freshly ground black pepper</li></ul>

<ul class="equipment-main-list"><li class="equipment-single-item">23cm (9-inch) fluted tart tin with removable base</li><li class="equipment-single-item">Baking beans or rice (for blind baking)</li><li class="equipment-single-item">Baking parchment</li><li class="equipment-single-item">Rolling pin</li><li class="equipment-single-item">Pie weights or ceramic baking beans</li></ul>

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Start with the pastry. Place the flour and salt in a large bowl and add the cold cubed butter. Using your fingertips, rub the butter into the flour until the mixture resembles breadcrumbs. Working with cold butter and handling minimally keeps the pastry flaky by preventing the butter from melting before baking.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>Add the ice-cold water one tablespoon at a time, gently mixing with a knife until the dough just comes together. Be careful not to overwork the dough as this develops gluten, making your pastry tough. Form the dough into a disc, wrap in cling film, and chill in the refrigerator for at least 30 minutes.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>While the dough is chilling, prepare the caramelized onions. Heat the butter and olive oil in a large, heavy-bottomed saucepan over medium-low heat. Add the thinly sliced onions and a pinch of salt. Cook gently for about 30-40 minutes, stirring occasionally. The low, slow cooking allows the onions' natural sugars to develop without burning.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>When the onions are soft and golden, sprinkle over the sugar and continue cooking for another 5-10 minutes until they turn a deep amber color. Add the balsamic vinegar and thyme, then cook for another 2 minutes to intensify the flavors. Remove from heat and set aside to cool.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Preheat your oven to 190°C (170°C fan/375°F). Roll out the chilled pastry on a lightly floured surface to about 3-4mm thickness, making it large enough to line your tart tin with a slight overhang. Gently drape the pastry over your rolling pin to transfer it to the tin.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Press the pastry into the tin, ensuring it gets into all the fluted edges. Trim any excess pastry, leaving about a 1cm overhang to allow for shrinkage. Prick the base with a fork, then line with baking parchment and fill with baking beans or rice. This blind baking step ensures your pastry base cooks through and doesn't become soggy.</li><li class="MethodStepper"><h4 class="step-title">Step 7</h4>Blind bake for 15 minutes, then remove the beans and parchment and bake for a further 5-7 minutes until the pastry is dry and just starting to color. If any cracks appear, patch with a small piece of leftover raw pastry. Reduce the oven temperature to 180°C (160°C fan/350°F).</li><li class="MethodStepper"><h4 class="step-title">Step 8</h4>To prepare the custard filling, whisk together the eggs in a large bowl. Add the cream, milk, half of the grated cheese, nutmeg, salt, and pepper, then whisk until well combined. The protein in the eggs will set as the quiche bakes, creating that distinctive silky, wobbly texture.</li><li class="MethodStepper"><h4 class="step-title">Step 9</h4>Spread the cooled caramelized onions evenly over the base of the pastry case. Pour the egg mixture carefully over the onions, making sure not to overfill the case. Sprinkle the remaining cheese on top.</li><li class="MethodStepper"><h4 class="step-title">Step 10</h4>Bake in the preheated oven for 25-30 minutes until the filling is set but still has a slight wobble in the center. This gentle jiggle indicates the perfect custardy texture; over-baking will make it rubbery. The top should be golden and puffed slightly.</li><li class="MethodStepper"><h4 class="step-title">Step 11</h4>Allow the quiche to cool in the tin for at least 15 minutes before removing. This cooling period allows the custard to set fully and makes the quiche easier to slice. Serve warm or at room temperature with a fresh side salad.</li><li class="MethodStepper"><h4 class="step-title">Step 12</h4>For the best flavor, you can make this quiche a day ahead and refrigerate it overnight. The flavors will develop beautifully, making it perfect for entertaining. To reheat, cover with foil and warm in a 160°C oven for about 15-20 minutes.</li></ol>