Preheat the oven to 350℉. Line a loaf pan with parchment paper and set aside.
In a medium bowl, mix together the flour, matcha and baking powder. Set aside.
In a large bowl, cream together the butter and sugar until light and creamy. Slowly mix in the eggs one at a time until fully incorporated. Mix in the sour cream and vanilla until fully combined.
Slowly mix the dry ingredients into the wet ingredients until just combined.
Pour the batter into the prepared loaf pan and bake in the oven for around 65 minutes, or until a toothpick comes out clean.
Allow to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.