Ok. Let's start with the cap. Cut out your mushroom cap, pin it onto your fabric of choice, and cut 4.
Sew two panels together along one side. Then repeat with the remaining two panels. I used the backstitch throughout this project for joining pieces together. It is a strong stitch and will hold things together when you stuff them.
Now, open the panels, lay them flat, and sandwich them together, right sides facing. Pin and stitch all the way along the top as shown above, making sure to stitch through the seams.
This is how they should look when you sandwich them together.
If you have done this correctly, it will look like this when you remove the pin and open it up.
Now flip that puppy inside out and you have the top of your mushroom cap! Ain't it cute?
This is the point at which you will want to embellish your mushroom cap. I cut little circles out of black felt to stitch onto mine, but you can do just about anything you want here. If you're not a stitcher, you could use fabric glue to apply little pieces of felt, sequins, buttons, or anything else that tickles your fancy.