Double Streusel Coffee Cake

Mumbai is rain haven but this year it has been heart-breakingly dry. So no dark clouds and heavy downpour  this time.  But I am hopeful. I scan the sky every day for the rain clouds and I plan on having hot steaming coffee sitting on my balcony. So all these thoughts brought coffee to mind. Since it is too hot to have coffee now I decided to make a coffee cake. But not a plain one. Where is the fun in that. So I spied a half empty bottle of mayonnaise and that was added to the list of ingredients. And of course to add that surprise element decided to make a streusel cake. Not just a single layer but a double streusel. And when I started eating the cake slice I could feel the hidden streusel layer. I spent a lot of time while clicking pics just to get that hidden streusel layer. So enjoy this super crumbly cake.

Ingredients

For the Streusel layers
½ cup brown sugar
½ cup all purpose flour
2 tbsp granulated sugar
¼ cup walnuts
4 tbsp butter
1 tsp cinnamon powder

For the cake layer
2 cups cake flour
1 ½ tbsp coffee powder
4 egg yolks
2/3 cups mayonnaise
1 cup sugar
5 tbsp butter
7 tbsp milk
½ tsp baking powder
½ tsp baking soda
1 tsp vanilla essence

Preheat the oven to 180 degrees Celsius. Take a 9” springform cake tin. Line the base with butter paper and grease the bottom and sides really well.
First make the streusel. Put the walnuts and both the sugars in a mixer and give it two short pulses. Add the flour, cinnamon powder and butter and pulse once. You will have a rough and grainy paste. Take out 1/3 of the streusel and keep aside.
Mix the egg yolks, ¼ of the mayonnaise and vanilla essence. In a separate bowl combine the flour, coffee powder, sugar, baking powder and baking soda. Add the butter and remaining mayonnaise and pulse so that the dry ingredients are moistened. Keep beating for about a minute so that more air is incorporated into the batter. Add the yolk mix in 3 batches, beating well after each addition. Now pour half the batter in the springform tin. Smoothen with a spatula. Sprinkle 1/3 of the streusel on the batter. Evenly spread the remaining batter on top. Then sprinkle rest of the streusel.
I usually wrap a thick roll of newspaper around the tin to ensure even baking.
Bake for about 55 minutes. Take care that the top most streusel does not get burned. Once it is cool take it out of the springform tin. When you cut into the cake you can see  the buttery streusel layer in the middle.