Frozen Panda Cake

INGREDIENTS:-
200 gr. butter
1 - 1.5 cup sugar (depending on how sweet you want it)
50 gr. butter
4 tbsp sugar
4 tbsp unsweetened coco powder
4 tsbp milk
1 egg
1 cup flour
1 liter milk
1 tsp vanilla or 1-2 piece mastic gum
for the sauce

METHOD:-

1. Heat butter in a pan. Add flour and sugar. Stir with a wooden spoon on medium heat constantly approximately for 5-7 minutes.
2. Add milk. Stir constantly until it thickens up.
3. Add mastic gum if you can find it. (Read Haalo's post to learn more about mastic gum) [Gum mastic can easily be purchased from Middle Eastern stores or from Amazon]
4. Pour cold water in a big and shallow pot. Place the pudding pot in the big shallow one so that the pudding pot is surrounded by cold water. Beat pudding with electric mixer on medium to high for 15 minutes. This will air up pudding and give it a nice texture. 
5. Wet a 2 or 3 quart glass dish. Pour pudding into the glass dish. Cover with a clear wrap and put in freezer.
6. For the sauce, melt butter. In a mixing bowl beat butter, egg, sugar, coco powder, and milk. Add milk one tbsp at a time to lighten the sauce up.
7. Spread the coco sauce on pudding which should be slightly firm by now. Put it back in the freezer.
8. Take Panda cake out of the freezer 10 minutes before serving to give it a little time to warm up and be ready to be cut. Put the rest back into the freezer.