In a large mixing bowl, combine the all-purpose flour and vanilla protein powder.
Add eggs, milk, melted butter, vanilla extract, and a pinch of salt.
Whisk until the batter is smooth and free of lumps.
Let the batter rest for 15 minutes.
Heat a non-stick pan over medium heat.
Pour a small amount of batter into the pan and tilt it to spread the batter thinly.
Cook for 1-2 minutes until the edges start lifting, then flip and cook the other side briefly.
For the filling, mix softened butter, brown sugar, ground cinnamon, and vanilla extract in a bowl until it forms a paste.
Spread a thin layer of the cinnamon filling over each crepe while still warm.
Roll up the crepes carefully to create a cinnamon roll-like shape.