Preheat the oven to 300 degrees Fahrenheit and line a loaf tin with baking parchment. Add the coconut flour, baking soda, xanthan gum, yeast, salt and erythritol to a large mixing bowl, stir together to combine.
Add the melted butter to the bowl along with the lemon juice and warm water. Beat together to combine. You should have a thick crumb as the mixture begins to bind.
Crack the eggs into a separate bowl. Whisk together for a few minutes. The eggs should be well beaten, fluffy and increased in volume.
Pour the beaten egg into the crumb mixture. Whisk together until well combined. You should have a thick yet smooth and pourable batter.
Spoon the batter into the prepared loaf tin. Smooth over the batter with a spatula so that the surface is even and level.
Transfer to the oven to bake for 35-40 minutes. The bread should be cooked through, firm and golden brown on top. Set aside to cool before slicing to serve.