The most 'puff' happens when you bake the dough covered - a deep roasting pan eg
-for the first 15 mins then uncover & bake till brown. It also helps to punch a small hole in the bun when you take it out of the oven to let steam out.
This all applies only to puffs, not to eclairs.

Just add two egg white beaten to a stiff peak to a 1lb recipe and add at the very last of ingredients.

Are you looking for a crisper, drier puff? Shirley Corriher writes in Cookwise to use more egg whites and less egg yolks to achieve this. I'd give you proportions, but I don't have my copy of the book as my Mom is borrowing it. If you don't have it, I'm sure your library will.

For those of us who would love to answer this but have never been to a Seattle's Best, give us some specifics about the kind of cookie you're looking for, a description of some sort. Are you looking for an eclair, a puff, or a cookie? The three are alike, but your question makes it seem that they are.

A "firmer" eclair or puff is obtained by baking the dough for the time specified, immediately cutting a small slits into the cracks in the puffs, then sliding the pan back into the oven, shutting the heat off, and leaving the pan in the oven for 10 additional minutes. When the puffs are cool enough to handle, cut off the tops of each puff and remove any dough that is still soft. Allow to dry out for an hour or so before filling.