Add the flour, baking powder, granulated sugar, milk, vanilla, and melted butter to a small bowl and stir until combined.
One the dough is solid, drop onto a clean and slightly floured surface.
Use your hands to flatten dough into a rectangle .
In a small bowl, melt the butter, brown sugar, and cinnamon for about 1 minute. (Depending on how cold your butter is.) Stir well.
Pour filling over dough rectangle and then roll up into a cinnamon roll shape.
Place roll into mug (I prefer to use a standard size mug, nothing too wide). Make sure your mug is sprayed with non-stick spray or greased.
Heat roll in microwave for 90 seconds. If the dough appears WET on top, it may need to heat for a few more seconds. (10 second increments.) If the dough appears dry the cinnamon roll is done. You can also test with a toothpick.
Stir confectioners sugar and milk together in a bowl until smooth.
Pour over warm cinnamon roll in the mug or invert the roll onto a plate and pour glaze over top.