Place yeast in a small bowl and pour warm water over it. Stir with a spoon to break up the yeast. Set aside for 2 to 3 minutes.
In a small saucepan, scald milk. Add butter and stir until melted. Remove from heat and let cool until lukewarm.
In a mixing bowl, beat eggs and egg yolks with an electric mixer. Add sugar and salt and continue to beat until mixture is thick and pale. Add vanilla, Grand Marnier, zests and yeast mixture. Combine. Beat in 1/2 of flour gradually. Add milk mixture alternately with remaining flour while beating on medium speed. Add additional flour if the dough is sticky. Mix in currants, sultanas and almonds.
Transfer dough to a clean large bowl. Knead using a large wooden spoon until the dough pulls away and doesn't stick to the spoon, about 8 to 10 minutes. Transfer dough to a large buttered bowl and turn to coat. Cover with cling film. Place in a warm place until dough reaches the top of the bowl, about 1 to 2 hours.
Punch the dough down, re-cover the bowl and allow to rise again.
Lightly grease 3 ring cake tins. In a small bowl, combine crumb topping ingredients. Place equal amounts of topping in the bottom of each tin.
Preheat oven to 180 C / Gas mark 4.
Punch the dough down again. Turn out onto a lightly floured surface. Knead for 1 minute. Cut into thirds and transfer dough to prepared tins. Cover loosely with cling film. Allow to rise to the top of tins. Beat remaining egg and brush the top of the dough.
Bake in preheated oven until golden brown and hollow sounding when tapped, about 30 to 45 minutes. Immediately turn out onto a cooling rack so bread does not stick to the tin. Cool before serving.
Eleanor, I knew with your anadama bread that you were some kind of bread genius, but this bread is too much -- it's wonderful. My dad says it's the best bread I've ever baked (and I've baked quite a few now). - 14 Jul 2008
Delicious! My husband is Polish and I make this every Easter to give to his family! I bake the Babka in 4 loaf tins instead of using the ring tins, and it works out really well. This is a wonderful recipe, one I have made part of our Easter tradition, thank you! - 14 Jul 2008
Really tasty Babka! It was the best when it was still warm ... and with some butter spread on it !! My family enjoyed it. I really like the orange flavour! - 14 Jul 2008