Whisk the flour, protein powder, sugar, and salt in a large bowl.
2 cups all purpose flour, 1/3 cup flax meal, 3/4 cup protein vanilla powder, 1/4 cup granulated sugar, 1 teaspoon salt
Pour the milk into a microwave-safe bowl and add the butter. Microwave on for 45 seconds, until the butter mostly melts and the mixture it’s warm to the touch and is about 110°F, but not higher. Whisk in the yeast until dissolved.
3/4 cup whole milk, 3 Tablespoons unsalted butter, 2 1/4 teaspoons instant yeast
Pour the milk and butter mixture over the flour mixture and add the egg. Use a wooden spoon or rubber spatula to stir to combine, until a dough forms. It should turn shaggy and become difficult to stir. Turn the dough out onto a well floured work surface and use floured hands to knead the dough for 3-4 minutes. Add more flour as needed if the dough is soft or sticky. Place in a lightly greased bowl, cover, and rise for 15 minutes while you prep the filling ingredients. It should puff up slightly but not quite double in size.
1 large egg
Turn the dough out onto a generously floured work surface and use a rolling pin to roll the dough into a 9x14-inch rectangle.
Spread the very soft butter over the dough, leaving a 1/2 inch border around the outside. Sprinkle with the brown sugar and cinnamon. Use your hands to spread it gently.
6 Tablespoons unsalted butter, 1/2 cup light brown sugar, 1 Tablespoon cinnamon
Working from the long end, roll the dough into a log. Place your hands at each end of the log and give it a gentle squeeze to compact it slighty.
Cut into 10-12 even rolls. I like to use unflavored dental floss for best results. Or gently saw a sharp knife back and forth, being careful not to squish the edges down.
Place them in a greased 9x13-inch baking dish. Cover with a towel and place in a warm place for 60-90 minutes to rise, or until doubled in size. I like to preheat my oven to the lowest temperature, turn it off, then place the dough in the oven to rise. Remove them from the oven when they’re done rising.
Preheat the oven to 350°F. Bake for 25-30 minutes or until the tops are light golden brown. The internal temperature should be between 190-200°F. Let them cool while you make the icing.
Place the cream cheese, protein powder, milk and powdered sugar in a medium bowl and mash again with the fork then use a whisk to mix until smooth. Spread the frosting over the warm cinnamon rolls.
8 ounces cream cheese, 1/2 cup vanilla protein powder, 1/4 cup powdered sugar, 1/4 cup milk