Preheat your oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line it with parchment paper for easy removal. Set aside.

Mix wet ingredients: In a large mixing bowl, whisk together the egg, milk, avocado oil, and vanilla extract until well combined. This will ensure the bread has a moist and tender texture.

Mix the gluten-free flour, protein powder, coconut sugar, baking powder, and cinnamon. Avoid overmixing to keep the bread light and fluffy.

Create the swirl: In a small bowl, combine the coconut sugar and cinnamon for the swirl. Pour half of the bread batter into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture over the batter. Pour the remaining batter on top and sprinkle the rest of the cinnamon-sugar mixture over it. Use a knife or skewer to gently swirl the cinnamon sugar into the batter for a marbled effect.

Bake: Bake the bread in the preheated oven for 45-55 minutes, or until a toothpick inserted into the center comes out clean. Baking times may vary, so start checking around the 45-minute mark.

Cool: Remove the bread from the oven and allow it to cool in the pan for 10 minutes. Then, transfer it to a wire rack to cool completely before adding the glaze.

In a medium-sized bowl, beat the softened cream cheese until smooth. Gradually add the powdered sugar, mixing well. Add the milk and vanilla extract, stirring until the glaze reaches your desired consistency. If it’s too thick, add a little more milk; if it’s too thin, add more powdered sugar.

Drizzle the Glaze: Once the bread is completely cool, drizzle the cream cheese glaze over the top. Use a spoon or piping bag for even coverage. Allow the glaze to set for a few minutes before slicing the bread.