Preheat your oven to 300°F (150°C) and prepare a 4x4 inch square pan with parchment paper or grease it.

In a mixing bowl, whisk together the eggs and avocado oil until frothy, about 1-2 minutes. Optionally, add erythritol for sweetness.

Stir in the plain Greek yogurt until smooth and blended, watching for lumps.

In another bowl, mix blanched almond flour, protein powder, baking powder, xanthan gum, and salt until well combined.

Gently fold the dry mixture into the wet mixture using a spatula until just incorporated.

Pour the batter into the prepared pan and smooth the top. Bake for 50-55 minutes until golden brown and a toothpick comes out clean.

Let the bread cool in the pan for about 15 minutes, then transfer to a wire rack to cool completely before slicing.