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 slow cooker lightly sprayed with non-stick cooking spray, sprinkle with pecans if desired. Place a paper towel on top of slow cooker & 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, & cinnamon for the frosting. Glaze with the frosting or serve on the side for your dipping pleasure.