Preheat your oven to 350°F (180°C).
In a mixing bowl, combine the flour, baking powder, and sugar.
In another bowl, soften the butter. Then whisk together the applesauce, Greek yogurt, and vanilla extract.
Add the wet ingredients to the dry ingredients and stir until a dough forms.
Knead in the protein powder until fully incorporated into the mixture.
Roll out the dough into a rectangle about 1/4-inch thick.
In a small bowl, mix together the brown sugar, ground cinnamon and melted butter.
Starting at one end, tightly roll up the dough and slice it into 1-inch thick rounds.
Place the cinnamon buns into the prepared baking dish and bake for 20-25 minutes, or until golden brown and cooked through.
Enjoy!