Tarte aux quetsches

Activate the yeast. Stir the fresh yeast into lukewarm milk and leave it briefly until it is evenly dispersed and lightly foamy. The yeast is evenly dispersed and the surface shows light foaming. A short activation confirms the yeast is dispersed before the enriched dough is mixed. The milk should be lukewarm, not hot.

Knead the raised dough. Combine the dough ingredients and knead until the soft mixture becomes smooth and elastic. The dough is smooth, elastic and soft, and pulls away from the bowl in stretchy strands. Kneading gives the raised tart enough structure to carry dense fruit. Scrape the mixer only when it is stopped.

Proof the dough. Cover the dough and let it rise until clearly expanded and aerated. The dough is visibly expanded and airy, though not necessarily fully doubled. A moderate first proof keeps the base light without making it too bread-like. Keep away from excessive heat that would melt the butter.

Prepare the quetsches. Dry the plums well, split them lengthwise and remove every stone while keeping the halves identifiable. About 940 g pitted fruit remains, with the halves intact and no pits left among them. Locking the pitted fruit weight controls the very high fruit load. Use a stable board and keep fingers clear of the knife.

Assemble the first layer. Press the risen dough evenly into the tin, arrange the plums densely and scatter over the first portion of sugar. The dough is even and the quetsche halves form tight concentric rows with little empty space. Dense arrangement gives the Alsatian tart its fruit-forward character. Do not press fruit so deeply that it tears through the dough.

Start the bake. Bake the fruit-topped dough until the base begins to set and the quetsches soften. The dough edge is beginning to colour and the quetsches have softened and released visible juice. A first bake sets the base before the custard is introduced. Hot fruit juice can burn; keep the tin level. Keep the oven at 180 °C.

Mix the cinnamon custard. While the tart is in its first bake, whisk the eggs, cream, remaining sugar and cinnamon until smooth. The custard is smooth, evenly speckled with cinnamon and has no visible egg streaks. Preparing the custard during the first bake avoids unnecessary extra elapsed time. Keep the eggs and cream refrigerated until this step.

Finish with the migaine. Pour the custard between the softened plums and return the tart to the oven until the filling is safely set. The custard reaches at least 71 °C, the centre is set with only a slight wobble, and the quetsche pieces remain visible above the filling. The second bake safely sets the migaine without losing the identity of the fruit pieces. Measure the custard in the centre with a clean thermometer.

Cool before cutting. Leave the finished tart on a rack for 30 minutes so the custard and fruit juices settle. The custard has stopped bubbling, the fruit juices have settled and slices hold together. Cooling stabilises the migaine and keeps hot fruit syrup from running. Refrigerate leftovers within 2 hours and keep at 4 °C or below.