Add the flour, brown sugar, butter, milk, egg, yeast, vanilla extract, and salt to an electric stand mixer bowl and knead the dough for 10 minutes until you achieve a smooth dough. If kneading by hand, knead for 20 minutes on a well-floured surface.
Then, transfer the dough to a greased bowl, cover with plastic wrap, place it in a warm environment, and allow the dough to rise for 1 hour or until double in size.
Meanwhile, make the cinnamon and sugar filling. Mix the butter, brown sugar, and cinnamon into a small bowl until you achieve a paste-like consistency.
After the dough has doubled in size, flour a surface and roll out the dough into a rectangle.
Spread the cinnamon filling all over the top of the rectangle. Roll up the dough tightly and cut into 8 even rolls.
Place the cinnamon rolls into a greased baking pan, cover with plastic wrap, place in a warm environment, and let it rise for 30 to 45 minutes.
When the rolls have doubled in size, preheat the oven to 350 F ( 180 C ) and bake for 15 to 20 minutes.
After you remove the rolls from the oven, allow them to cool for 10 minutes before you add the icing sugar on top. Sprinkle more cinnamon on top and serve them immediately!