German Hazelnut Marble Cake

I often make Marmorkuchen for my Dad, he enjoys it a lot. My beautiful Bride tried Marmorkuchen for the first time the other day, and enjoyed it, and so I wanted to make one for her. But also, I wanted to try and improve it. And, of course, immediately thought of adding hazelnuts. I settled on 1/2 cup, which would mean that the regular recipe would call for 1 cup of hazelnuts, as this is half the recipe compared to the other, but you can play with that. I used spelt flour, you need to add a little more than if you were to use all-purpose flour, due to the lower gluten content; this makes the dough come out much darker in colour, so, if you prefer more yellow, use all-purpose. 1/2 Packet Dr. Oetker Vanilla Sugar and Baking Powder translates to about 1 and 1/2 tsp, maybe a little more. This tasted really good, of course it tasted the best just after being cooked, it was a little dry later on.

German Hazelnut Marble Cake
125 g Butter
125 g Sugar
1/2 Packet Dr. Oetker Vanilla Sugar
2 eggs
1-2 Tbsp Frangelico
some salt
250 g all-purpose flour/ 270 g spelt flour
1/2 Packet Dr. Oetker Baking Powder
125 mL of milk
15 g cocoa
12.5 g sugar
1/2 cup toasted hazelnuts, ground fine
1-2 Tbsp. milk

Stir the butter until it is smooth, then alternately add the sugar, vanilla sugar and eggs. Add the rum-aroma and salt last. Mix the baking powder with the flour, then add it through a sieve, alternately with the 1/8 L of milk (only add enough milk so that the dough falls stiffly from the spoon). Transfer about 2/3 of the dough to a greased Springform pan. Add the cocoa and sugar, again sieved, to the remainder of the dough. Add the ground toasted hazelnuts. Add enough milk to make it of a consistency that it falls stiffly from the spoon. Add the chocolate dough on top of the yellow dough, then draw a fork through the underside dough, twisting the dough in a spiral so that some of the yellow portion comes to the top. Continue this technique all around the Springform pan. Bake at 350C for 75 minutes, the last 10 minutes with the oven off.