Preheat the oven to 180°C.
Toss the squash with oil and seasoning, roast for 30 minutes, then cool and set oven to 170°C.
Roll out pastry to 3mm thick, line a 24cm tin, prick the base, and chill for 20 minutes.
Blind bake with parchment and beans for 30 minutes, then bake for 10 more minutes until golden.
Distribute roasted squash, Stilton, and membrillo over the pastry base.
Whisk eggs, cream, and crème fraîche, pour into the quiche, and bake for 40 minutes at 170°C.
Simmer 100ml water, sugar, cinnamon, and star anise for 1 minute before adding lemon juice and cooling.
Segment the pomelo, marinate in spiced syrup for an hour, then strain and reserve juices.
Blanch sprouts and shallots for 2 minutes, halve them, toss with oil, and roast at 200°C for 20 minutes.
Combine sprouts, shallots, pomelo, coriander, and dressing ingredients in a bowl and mix gently.
Slice the quiche and serve with the warm sprout and pomelo salad.