Solution

Thanks for all of the suggestions for fastening the potholder pieces together. While crocheting the two sides together would have been pretty quick, I didn't want to add any more length/width to the finished potholder, nor did I want to add extra bulk at the edges. I also didn't want to hand sew with thread - that would have taken way longer than I wanted to spend.

I did come up with a plan, though. Look:

Ta-da!

What did I do? I decided to exploit an existing design element. I sewed the two layers together using a yarn needle and some of the household cotton from the bottom layer to backstitch the pieces together running the stitches through the eyelets created by the yarn overs.

Here is how it looks on the top side.

Picks up the blue on top nicely, doesn't it?

And the back looks like this.

Sort of a "running stitch" look

On the reverse, the eyelets sort of disappear, as they are "filled up" with the backstitching, but that's fine by me: the project is complete; it was a quick finishing job; and the potholder is ready for action, hanging on the side of the new range hood/microwave.

Where's the hot stuff?

And as we wouldn't have a Finished Object post without some specifications:

• Pattern: Grandmother's Favorite Dishcloth
• Top: Bernat Handicrafter (Pretty Pastels)
• Bottom: Sugar 'n Cream (Light Blue)
• Needles: size 6 (US)

The pattern is a free one available on a heap of web sites - this is just the first place that I saw it.

Note: If you want to give this a go, remember to carefully match up the eyelets. Also, I laid the blue layer down with the garter stitch running horizontally then placed the pastel layer on top with the garter stitch running vertically. The 90° rotation of the grain of the fabric should prevent the whole thing from stretching out of square.