Uso Coffee Cake

• 12 greased (pan)
• 2 eggs
• 1/2 mixture
• 240 ml buttermilk
• 220 gr brown sugar
• 100 gr sugar (white)
• 60 gr walnuts (chopped)
• 60 gr walnuts (chopped)
• 28 gr baking powder
• 16 ml soda water