Knead 200 g flour, ground almonds, baking powder, sugar, 1 pinch of salt, butter in pieces, 1 egg and possibly 1 tablespoon of ice-cold water first with the dough hooks of the hand mixer and then briefly with your hands until smooth.
Pour Amarettini into a plastic bag, close the bag. Crumble finely with a rolling pin. Grease a tart tin with a removable base or springform pan (26 cm Ø). Wash, de-stem, halve and stone the plums
Roll out 2/3 of the dough onto some flour and roll it out round (approx. 30 cm Ø). Line the mould with the dough, pressing the edges into the grooves. Prick the base of the dough several times with a fork. Sprinkle with Amarettini crumbs. Spread plums on top
Form a roll (approx. 28 cm long) from the remaining dough and roll out to a strip (approx. 15 x 28 cm) on some flour. Cut lengthwise into strips (approx. 1 1/2 cm wide) with a dough wheel. Place on the plums in a grid pattern and press down at the edges. Whisk 1 egg yolk and 1 tsp cream. Spread the dough strips with it. Bake in the preheated oven (electric cooker: 200 °C/circulation: 175 °C/gas: level 3) for approx. 30 minutes. Let them cool down. Sprinkle with sugar crystals