|Sections 1 and 2|
Flip the quilt over and now lay one side of the batting down in the little ditch (it should completely fill the ditch, don't cut it half way) and trim it evenly so it lays flat. Now do it to the other side.
Overlap both sides of the batting and cut down the middle, be careful not to cut your top! Go slowly, this is a little hard. When you are done your batting should fit in nicely and not be lumpy. The edges should be butted up against each other.
Fold your backing back. Take one side (I chose the left side in this picture) and fold it over the batting and press. This will make a nice crease.
Now take the fabric on the right side and trim so it is a 1/2 inch larger than the raw edge of the left side. Press under a 1/4 inch seam allowance and pin.
Sew down that edge and you are almost done. I have heard of people being able to do this by machine but that would not be me!
Not go back and quilt over that seam. Mine turned out great, very flat and no lumps or bumps.
This may not be a super quick way but it was something I could do in bits of time I had. I have wanted to try this for a long time now but was afraid to use it on a quilt I loved. This was a good experiment and one I will keep in my tool box. I am going to try and finish this up over the weekend so you can see the finished project.
If this is confusing sorry, I have never done this before. Please feel free to email me or leave a comment and I will try to help you.