Preheat oven at 180C (350F). Line two medium size loaf pans with parchment paper and slighlty grease. Set aside.
Combine flour, salt and baking powder until incorporated.
In a separate bowl, cream butter and sugar together. Add eggs one at time then add the vanilla. Mix until just well combined.
In a measuring cup, combine milk and sour cream.
Gradually add dry ingredients and milk mixture alternately to the wet ingredients. Mix until thoroughly incorporated. Do not overmix.
Equally separate batter into two bowls. Add cocoa powder into one and matcha on another. Mix well until just well combined.
Place dollops of batter alternately into your loaf pan making two layers. Swirl the batter using tha back of a spoon or anything similar.
Bake for 30-40 minutes or until the center sets. Cool for about 30 minutes and slice into equal portions.
