Put flour, yeast, butter, oil, sugar, eggs, sour cream, milk, salt and vanilla in a mixer bowl with a dough hook and knead together for about 10 to 12 minutes until you get a smooth, slightly sticky dough.

Cover the bowl with plastic wrap or a damp towel and let the dough rise until its volume is doubled (about one hour at room temperature).

Break the chocolate into squares and place in a bowl. Add butter and melt together in the microwave or on a Bain Marie until everything is melted and the mixture is smooth.

Add ground almonds and mix well until smooth.

Cool the mixture at room temperature until it reaches a comfortable texture for spreading.

Divide the dough into two parts.

On a floured surface, roll out each part into a rectangle about half a centimeter thick.

Spread half of the filling in a uniform layer.

Fold the dough into a rectangle such that the filling is in between two sheets of dough.

Roll out the dough with the filling to a thickness of about half a centimeter.

Cut the rolled dough into large triangles.

Roll each triangle into the shape of a rugelach and place close together in a greased 26-centimeter (10-inch) round pan.

Repeat with the second part of the dough and the rest of the filling to make more rugelach. The cake should look like a flower of rugelach.

Cover the cake and let rise for 50 to 60 minutes in a warm place, until it almost doubles its volume.

Brush the cake gently with a beaten egg.

Bake for 30 to 35 minutes or until the cake is risen, golden and firm.

In a small pot, put water and sugar and heat until a boiling syrup is formed and all the sugar melts.

Brush the cake generously with syrup and serve.