Mix chopped nuts, cinnamon and ¾ cup sugar in a bowl and reserve.
Whip margarine or butter with sugar until fluffy and creamy. Add in eggs, one at a time, beating after each addition and vanilla.
Mix flour, baking powder, baking soda and salt and add to egg mixture alternating with the sour milk.
Lightly grease and flour a tube cake pan.
Pour cake mixture in layers: Start with a layer of the reserved nut mixture, cover with a layer of the sour cream mixture and place a layer of apple wedges on top. Repeat layers.
Bake in preheated oven to 350°F (180°C) for 50 to 60 minutes or until set and tester comes out clean.
Other coffee cakes:
Cinnamon cake with streusel topping