Preheat the oven to 350°F (180°C) and line a loaf pan with baking paper.
In a mixing bowl, combine the dry ingredients: The almond flour, baking powder, cinnamon, and salt.
In another mixing bowl, combine the cream cheese with the butter and Erythritol. Using a mixer beat until smooth and fluffy.
Add the vanilla, sour cream, and liquid stevia to the cream cheese mixture and mix until well combined.
Once the mixture turns into a smooth and glossy batter, gradually 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 before removing it from the pan and slice. Serve at room temperature, optionally garnished with blueberries and a drizzle of cream.