Preheat oven to 180°C (350°F). Line a 9-inch x 5-inch loaf pan with a piece of parchment paper. Lightly oil the paper to make sure the bread doesn't stick to the pan. Set aside.
In a small mixing bowl, prepare the cinnamon swirl, whisk erythritol, and cinnamon. Set aside.
In a medium mixing bowl, whisk together eggs, sugar-free crystal sweetener, melted coconut oil (or butter), almond milk, and vanilla. Make sure that your coconut oil is not burning hot or it will 'cook' the eggs and create lumps. All your ingredients must be roughly at the same temperature, think room temperature, especially the eggs and almond milk. Cold ingredients just out of the fridge will solidify the coconut oil creating oil lumps. Otherwise, use melted butter to prevent this from happening. Set aside.
In a different large mixing bowl, whisk together the almond flour, coconut flour, and baking powder. Stir to evenly combine the flours.
Pour the liquid ingredients onto the dry ingredients.
Stir all the ingredients together with a baking spoon until it forms a consistent bread batter with no lumps. Combine for at least 1 minute to make sure the coconut flour fiber absorbs the moisture.
Transfer roughly half the bread batter onto the loaf pan.
Sprinkle half the reserved cinnamon/erythritol mixture, then add the remaining batter and sprinkle the remaining cinnamon/erythritol mixture on top of the bread.
Draw a knife through the batter and swirl to create a marble effect. See my picture in the post for tips.
Place the loaf pan in the center of your oven and bake at 180°C (350°F), fan-forced mode, if you can, for 15 minutes. After 15 minutes, decrease the temperature to 160°C (320°F) and cover the loaf pan with a loose piece of foil. This will prevent the top from burning and will allow the middle to bake slowly. Keep baking for 45-60 minutes in total, or until a toothpick inserted in the center of the bread comes out with little to no crumbs on it.
Cool for 10 minutes in the loaf pan, then lift out the cinnamon bread from the pan using the hanging pieces of parchment paper.
Transfer to a cooling rack to cool completely. It is a thick bread loaf and it usually takes 3 hours to fully cool. Be patient!
Store your bread in the pantry on a cake box for up to 3 or 4 days. Slice before serving to keep the bread crumb moist.
Enjoy as breakfast, teatime, plain, or with sugar-free chia seed jam.
Freeze the bread slices in an airtight box, making sure the slices don't overlap (or place a piece of parchment paper between each slice to make it easier to defrost individually. Defrost the slice the day before at room temperature, on a plate, don't overlap the slices.