It's the addition of sautéed onion that distinguishes the
Alsacienne from its better-known cousin, the classic quiche
300 gmspeck, cut into lardons2onions, thinly sliced8egg yolks6eggs250 ml (1 cup)pouring cream250 gmcrème fraîche2 tbspfinely chopped flat-leaf parsley½ tspfinely grated nutmegPâte brisée300 gm (2 cups)plain flour150 gmcold butter, coarsely chopped1 tspsea salt2-3 tbspchilled sparkling mineral water
For pâte brisée, process flour, butter and salt in a food processor until crumbs form, add mineral water, pulse until mixture comes together. Turn out, knead lightly, wrap in plastic wrap, refrigerate to rest (2 hours).
Preheat oven to 180C. Roll out pastry on a lightly floured surface to 3mm thick, line a 27cm-diameter, 5cm-deep tart tin, refrigerate to rest (30 minutes). Trim edges, prick base all over, then blind bake until light golden (8-10 minutes), remove paper and weights and bake until crisp (6-8 minutes).
Meanwhile, heat a frying pan over medium-high heat, add speck, stir occasionally until crisp (3-4 minutes), remove and set aside. Add onion to pan, stir occasionally until very tender (4-5 minutes), season to taste and spread over base of pastry case, then scatter speck over.
Reduce oven to 150C. Whisk yolks, eggs, cream, crème fraîche, parsley and nutmeg in a bowl to combine, season to taste and pour into pastry case. Bake until light golden and just set with a slight wobble in centre (35-40 minutes), stand for 15 minutes, then serve.