Preheat the oven to 350°F and line a loaf pan with parchment paper.
Add these ingredients to a large mixing bowl: almond flour, 1/3 cup of erythritol (set the remaining aside), baking powder, and coconut powder. Mix really well.
Add the almond milk, melted butter, sour cream, eggs, and vanilla and mix until a thick batter forms.
Add the remaining sweetener to another bowl. Mix with the cinnamon.
Pour half of the batter into the loaf pan. Add half of the cinnamon mixture on top. Then, add the other half of the batter . Top with the remaining cinnamon mixture. and use a knife or a spoon to swirl the batter.
Flatten the top and bake for 1 hour. Then, let it cool for 30-40. Enjoy!