How do I get Nooks and Crannies in my English muffins? I have tried making English muffins a few times. Each time the flavor was good but I didn't end up with the open interior texture that I expect from storebought English muffins.

I let them proof for the amount of time recommended by the recipe- about an hour. I cooked them on an electric skillet. They took a bit longer to cook than the recipe called for- about 5 minutes per side if I recall.

What do I have to do to encourage the formation of large holes and an open interior texture in my English muffins?
I found a great recipe for English muffins, which is a variation on Alton Brown's recipe.  Basically, the variation calls for adding a bit of baking soda after proofing the dough.

I've made this recipe a couple of times, with very satisfying results.  The yeast flavor is a bit strong for those used to store-bought, but I like it.