For the cherries Vlaai heat the milk and dissolve the yeast in it. Put salt and flour in a bowl, make a well. Add butter, sugar, oil and egg yolk. Add the milk and yeast mixture as well.
Using a food processor, knead the ingredients into a smooth dough. Then knead the dough again briefly by hand on a floured work surface.
Cover the dough with a damp tea towel and let it rise in a warm place for about 30 minutes.
For the filling, drain the cherries in a sieve and collect the juice. Dissolve the cornstarch in a little juice. Heat the remaining juice in a saucepan and stir in the dissolved cornstarch and sugar.
Then add the cherries and let sit for about 30 minutes (for binding). Preheat the oven to 180 degrees. Knead the dough well again.
Grease a cake pan (diameter 32 cm) well with butter. Roll out 2/3 of the dough round, to the size of the pie dish and place in the dish. Prick the dough several times with a fork and sprinkle with the breadcrumbs.
Spread the cherry filling on the dough. Roll out the remaining dough also to the size of the tart pan, place it on a firm surface and cut out the motif with a lattice punch, remove the excess dough.
Moisten the edges of the dough and then slide it onto the cake. Press the edges down firmly. Beat an egg and brush the surface of the cherries vlaai with it, then cover with d