Scrub the quince thoroughly with a cloth, remove the stalk, cut the fruit into eighths, place in a pan. Combine the water, sugar and 1 tbsp of lemon juice, pour into the pan, cover and bring to the boil. Reduce the heat, cook the quince over a medium heat for approx. 40 mins. until soft. Remove the pan from the heat, allow to cool slightly. Drain the quince, pass through a food mill and back into the pan (yields approx. 275 g). Add the remainder of the lemon juice, bring to the boil while stirring, turn down the heat, simmer over a low heat for approx. 10 mins., stirring frequently to form a thick puree, remove from the heat, leave to cool.
In a pan, whisk the milk and all the other ingredients up to and including the egg yolks, bring to just below the boil over a medium heat, stirring constantly. Remove the pan from the heat immediately. Stir the gelatine into the hot custard, then pour the mixture through a sieve into a bowl, cover and leave to cool, chill until the custard is just set at the edges. Stir the vanilla custard until smooth, fold in the whipped cream. Cover and chill the custard.
Prick the dough several times with a fork, sprinkle with sugar. Halve the dough lengthwise, then cut each half crosswise into approx. 9 strips. Place the dough on the back of a baking tray along with the baking paper.
Approx. 10 mins. in the lower half of an oven preheated to 220°C. Remove from the oven, leave to cool on a cooling rack.
Transfer the quince puree and custard to two piping bags with a smooth nozzle (approx. 16 mm in diameter). Pipe the quince puree and custard onto 6 pieces of puff pastry each, place on top of each other. Place the remaining pieces of puff pastry on top.