In a small bowl, mix together melted butter and vanilla; set aside. In a separate bowl, combine brown sugar and one teaspoon cinnamon. Roll biscuits in butter mixture, then in brown sugar mixture until well coated.
Place biscuits in a crock pot lightly sprayed with non-stick cooking spray, sprinkle with pecans if desired. Place a paper towel on top of slow cooker and cover with the lid. Cook on low setting for 2-3 hours. I found cooking on 2 hours was perfect, so be careful not to overcook.
After cooking, mix together the powdered sugar, milk, and cinnamon for the frosting.
Glaze with the frosting or serve on the side for your dipping pleasure.