Warm the milk until lukewarm. Add the yeast and sugar and it mix well. Leave to rest for 10 minutes until bubbles form on the surface—this means the yeast is activated. If no bubbles appear, the milk was too hot; discard and start again with cooler milk.
125 ml milk, 40 g granulated sugar, 2 teaspoon instant yeast
Add the yeast mixture to the flour, butter, lemon zest, egg yolk, and salt. Using a stand mixer with a dough hook, knead for 10 minutes until smooth. Cover with a towel and let rise in a warm place for 30 minutes until doubled in size.
350 g all-purpose flour, 150 g butter, 1 teaspoon lemon zest, 1 egg, 1 pinch salt
While your dough rises, melt the butter in a small saucepan. Remove from the heat and stir in flour, sugar, cinnamon, and the vanilla extract or sugar until you get fine crumbs.
butter to grease the pan, 150 g all-purpose flour, 75 g granulated sugar, 75 g butter, 2 teaspoon ground cinnamon, 1 teaspoon vanilla extract
Wash and drain the plums. Make crosswise cuts at both ends, then slice along one cut to open and remove the stone.
1 kg Italian prune plums
Preheat your oven to 200°C/392°F top to bottom heat.
Knead the risen dough briefly on a floured surface, then roll out to fit your baking tray. Grease the tray or line with parchment paper. Press the dough into the pan.
Arrange plum halves in overlapping rows on the dough. Sprinkle streusel on top.