Begin by preheating your oven to 400 degrees F.
Unroll your crust on a lightly floured surface. Then, brush the crust with melted butter and evenly sprinkle with cinnamon and sugar. Roll the crust up tightly and slice into 1/2-inch rounds.
Press these rounds, cut side down, into a clear glass 9-inch pie plate. Press until flat, covering the entire pan. Make sure there are no spaces between the rolls.
In a large bowl, toss the apple slices with the flour, sugar, and cinnamon until evenly coated. Then, pour the apples into the crust. It will mound up and almost seem to be overflowing. This is good.
Then, in a medium bowl, combine the butter, flour, and brown sugar with your fingers or a pastry blender until crumbly. Sprinkle the crumble over the heaped apples. Finally, sprinkle the whole pie with the sugar.
Bake the pie until the crust is golden brown and the filling is bubbly (about 50 - 60 minutes). (My oven tends to brown things easily, so I very lightly covered the top of my pie with tin foil for most of the baking process.) Once baked, remove form the oven and allow to cool completely on a cooling rack.
When the pie is cool, you can prepare the icing. In a small bowl, whisk together the powdered sugar, vanilla, cinnamon, and milk. If your mixture seems too thick, add a bit more milk. If it's too thin, add more powdered sugar. Transfer the icing to a pastry bag or a plastic bag with the corner cut off. Then, pipe the icing in a swirl (to resemble a cinnamon roll) on top of the crumble.