Preheat the oven to 375° F. Coat a muffin tin with nonstick spray.
FILLING
In a medium bowl combine the butter, brown sugar, and cinnamon. Set aside.
DOUGH
In a large bowl combine the flour, sugar, baking powder, and salt. Using a pastry cutter or a fork, cut in the butter until combined. You can also use you hands for this. Slowly add in the milk and stir to combine, forming a dough. Turn the dough out onto a lightly floured surface and knead in any extra flour that didn’t mix in.
Roll out the dough into a rectangle shape, approximately 1/4- inch thick. Spread the filling onto the dough evenly. Starting at the long end, tightly roll up the dough into a long log.
Cut the dough into 2 1/2 -inch long pieces for large muffin-rolls.
Place each piece into prepared muffin tins.
Bake for 15-20 minutes, or until the centers are baked. Remove from the oven and place the pan on a wire rack to cool.
ICING
Whisk together the powdered sugar and milk.
Loosen the muffins from the pan using a butter knife. Place on a plate and pour the icing on each muffin.