Chocolate Babka with Streusel Topping

From: Zehava Bloomberg

Instructions

Using challah dough: Chocolate babke filling is pretty much 1:1:1 ratio of dutch cocoa, sugar and confectioner's sugar. (For one babka, about 1/2 cup of each). Plus good semisweet chocolate chips or baking choc. - if you are using 1/2 measure, then use 1/4-1/3 cup chocolate chips. Mix all of those dry ingredients together. Roll out the dough, spread a thin layer of oil to cover the entire rolled out dough, then sprinkle dry mixture over in an even layer. Roll up lengthwise, fold roll in half & twist. Place in challah/loaf pan, brush with egg and sprinkle with a simple streusel topping (flour, sugar, margarine/butter). For the streusel: ½ cup all-purpose flour ¼ cup brown sugar, packed ½ stick unsalted butter ½ tsp ground cinnamon