Preheat the oven to 350°F and line a loaf pan with parchment paper.
In a mixing bowl combine the flour with the baking powder, cinnamon, and salt.
In another mixing bowl, combine the yoghurt with the olive oil and sugar. Using a mixer beat until smooth and fluffy.
Add the vanilla, sour cream, and honey to the yoghurt mixture and mix until well combined.
Add eggs one by one and beat well with the mixer. Fold in the flour mixture, and lastly add the blueberries and walnuts. Mix briefly with gentle moves.
Pour the batter into the prepared loaf pan and bake for 40-45 minutes until golden brown.
Allow the cake to reach room temperature, slice and serve.